Glenbeigh Off Site (GOS) Insulated Steel Frame Building … certificate/IAB080327 - GOS... · design of the panellised GOS Insulated Steel Frame ... An appropriately designed ground

Readers are advised to check that this Certificate has not been withdrawn or superseded by a later issue by contacting the NSAI Agrément 1 Swift Square, Northwood, Santry, Dublin 9. or online at http://www.nsai.ie/modules/certificates/uploads/pdf/IAB080327.pdf

IRISH AGRÉMENT BOARD CERTIFICATE NO. 08/0327 Glenbeigh Off Site. Damastown Way, Damastown, Dublin 15 Tel: +353 (1) 8990088 Fax: +353 (1) 8227009 Email: [email protected]

CI/SfB 81 28.6 Hh2 (e4)

Glenbeigh Off Site (GOS) Insulated Steel Frame Building System

Systèmes pour constructions Bausystem

NSAI Agrément (Irish Agrément Board) is designated by Government to issue European Technical Approvals.

NSAI Agrément Certificates establish proof that the certified products are ‘proper materials’ suitable for their intended use under Irish site conditions, and in accordance with the Building Regulations 1997 to 2008.

PRODUCT DESCRIPTION: This Certificate relates to the Glenbeigh Off Site (GOS) Insulated Building System, for the manufacture and installation of insulated cold-formed Light Gauge Steel Frame Buildings. The GOS Steel Frame Building System is certified in the applications defined below and can be used in purpose groups 1(a), 1(b), 1(c), 2(a), 2(b), 3, 4(a), 4(b), and 5 as defined in Technical Guidance Document to Part B of the Building Regulations 1997 to 2008. The system can be used for a variety of structures including domestic housing, apartment blocks, industrial and institutional buildings and can accommodate a wide range of custom designs. This Certificate is the principle Certificate and all other detail sheets related to the certification of the GOS Insulated Steel Frame Building System must be read in conjunction with this Certificate. This Certificate describes the basic principles of the system for all building forms certified.

USE: The system is certified in the following applications: 1. To provide the structure of a building up to 4 storeys

but not greater than 12m in height, which can accommodate a composite concrete profile metal deck or cold formed section floor.

2. The GOS system may be used in the construction of the top floor of a multi story building provided the system is constructed off a concrete/non-combustible podium/transfer slab.

3. GOS internal Non-load bearing Infill Panel can be used in all concrete and steel framed buildings that possess their own independent lateral stability systems. The infill panels are designed to resist their self weight only along with imposed wind loading due to the action of masonry cladding, which is tied to the studs using the stainless steel slot and channel wall tie system.

Certificate No. 08/0327 Glenbeigh Off Site (GOS) Insulated Steel Frame Building Systems

Glenbeigh Off Site (GOS) produces all cold-formed steel sections using (CNC) computer numerically controlled plant. GOS provide SealiteTM spray applied polyurethane insulation which fills the voids between the cold formed steel sections in the panels which form the inner leaf of the external envelope of a building. In addition to the spray applied polyurethane insulation, blocks of polyisocyanurate (PIR) rigid foam insulation are placed on the cavity side of the cold formed steel studs. The rigid foam insulation serves to encase the cold formed steel sections thus creating a "warmframe" environment for the steel frame. A breather membrane is installed on the cavity side of the rigid foam insulation. An air tight barrier/ vapour control layer, OSB and gypsum plasterboard clad the inner leaf of the cold formed steel panel. Site erection is carried out by a GOS licensed fabricator/installers, or by specialist sub-contractors under the supervision of GOS. Initial site development and completion of building works, after the steel frame system has been erected are the responsibility of the main contractor. DESIGN: The GOS Insulated Steel Frame Building System is intended for use where architect’s finalized construction and fire strategy drawings are available and satisfy the Building Regulations 1997 to 2008. The architect and engineer design team of the developer (the client) is responsible for the architectural drawings and overall building design to

comply with the Building Regulations. The GOS Chartered Structural Engineer is responsible for the final design of the panellised GOS Insulated Steel Frame Building System. The GOS Insulated Steel Frame Building System is designed for use in permanent buildings with a brick/block external wall finish with a wide range of traditional roofing finishes. The system may also be designed to incorporate NSAI Agrément approved alternative lightweight roofing and external wall cladding systems, however, written approval must be sought from GOS on the use of such lightweight claddings. The buildings are assembled using a panellised system (factory made and site assembled). MARKETING, DESIGN AND MANUFACTURE: The product is designed and manufactured by: Glenbeigh Off-Site Construction. Damastown Way, Damastown, Dublin 15. The product is marketed and erected by: Glenbeigh Off-Site Construction. Damastown Way, Damastown, Dublin 15.


1.1 ASSESSMENT In the opinion of the NSAI Agrément Board, the GOS Insulated Steel Frame Building System if used in accordance with this Certificate can meet the requirements of the Building Regulations 1997 to 2008, as indicated in Section 1.2 of this Agrément Certificate. 1.2 Building Regulations 1997 to 2008 REQUIREMENTS: Part D – Materials and Workmanship D3 – Proper Materials The GOS Insulated Steel Frame Building System, as certified in this Certificate, is comprised of ‘proper materials’ fit for their intended use (see Part 4 of this Certificate). D1 – Materials & Workmanship The GOS Insulated Steel Frame Building System, as certified in this Certificate, can meet the requirements for workmanship. Part A - Structure A1 – Loading The GOS Insulated Steel Frame Building System once appropriately detailed, designed and constructed has adequate strength and stability to meet the requirements of this Regulation (see Part 3 of this Certificate). A2 – Ground Movement An appropriately designed ground floor or podium slab can safely sustain the combined dead, imposed and wind loads of the system into the foundation structure without causing undue deflection to any part of the building. Part B – Fire Safety B1 – Means of Escaped in Case of Fire Windows in the ground or higher floors may be used as a means of escape in the case of fire. Where a window is required to provide an alternative means of escape, it must provide an unobstructed opening of not less than 850mm high by 500mm wide. The window should be positioned as required by BS 5588-1:1990 Fire precautions in the design, construction and use of buildings – Code of practice for residential buildings, and BS 5588-11:1997 Fire precautions in the design, construction and use of buildings – Code of practice for shops, offices, industrial, storage and other similar buildings, and in

accordance with Part B1 of TGD B of the Building Regulations 1997 to 2008. Any restrictor fitted, must be easy to operate. B2 – Internal Fire Spread (Linings) The plasterboard side of walls and ceilings is designated Class 0. It may therefore be used on the internal surfaces of buildings of every purpose group without restriction. B3 – Internal Fire Spread (Structure) (i) The GOS Steel frame system has been designed

and once boarded in accordance with Table 4 of this Certificate will have its stability maintained for a reasonable period in the event of Fire.

(ii) The separating wall specification shown in Figure 7 gives a minimum 60 minutes fire resistance between two or more buildings and offers adequate resistance to the spread of fire between those buildings.

(iii) The system can be easily designed to accommodate sub-divided fire resisting construction in accordance with Fire Certificate where it is necessary to inhibit the spread of Fire within the building.

(iv) The building details of the system incorporate suitable cavity barriers and fire stops to satisfy the requirements of section 3.3 to Part B of the TGD to the Building Regulations (see figure 7 & 8).

(v) An apartment, a house in a terrace and a semi-detached house are treated, as separate buildings therefore, must be separated by a separating wall (party wall) as shown in Part B of the TGD to the Building Regulations, Figure 7.

(vi) The load bearing elements specified in Table 4, Section 4 of this Certificate provide for 30 and 60 minutes fire resistance from either side, for a range of specifications.

B4 – External Fire Spread The external masonry walls have a Class 0 surface spread of flame rating and when installed and used in the context of this Certificate will provide adequate resistance to the spread of flame over the external walls and roofs and can satisfy the relevant requirements of this Regulation as indicated in Section 4.1 of this Certificate. Part C – Site Preparation and Resistance to Moisture C3 – Dangerous Substances Each dwelling ground floor must include a radon sump and provide the facility for radon extraction. Where it is shown, that protection from dangerous substances e.g. radon, is required an approved gas resistant membrane and gas handling system must be provided under the ground floor. GOS Insulated Steel Frame Building

Part One / Certification 1


System permits the easy incorporation of the appropriate membrane, sump and gas handling system. C4 – Resistance to Weather and Ground Moisture GOS Insulated Steel Frame Building System has adequate damp-proof courses and membranes to resist the passage of moisture from the ground (see Figure 9). Roof and external walls above site DPC level will have adequate weather resistance in all exposures to prevent the passage of moisture from the external atmosphere into the building as specified in section 4.6 of this Certificate. Part E – Sound E1 – Airborne Sound (Walls) Walls can be appropriately detailed and constructed to meet the airborne sound requirements of this Regulation (see also Section 4.4 and Figure 6 and 8 of this Certificate). E2 & E3 – Airborne and Impact Sound (Floors) Intermediate and separating floors can be constructed to meet the airborne sound requirements of this Regulation (see Figure 5). Part F – Ventilation F1 – Means of Ventilation Adequate ventilation openings are provided in internal and external walls and in roofs to meet this requirement. Walls and roofs used in the system can be designed and constructed so as to prevent any harmful effect from interstitial or inner surface condensation to comply with the requirements of BS 5250:2002 Code of practice for the control of condensation in buildings. F2 – Condensation in Roofs Adequate ventilation is provided in roofs to meet this requirement (see Section 4.3.2 of this Certificate). Part J – Heat Producing Appliances J1- Air Supply The system can provide an adequate supply of permanent combustible air if required by means of air ducts to obviate draughts within the room in which the fireplace is located. J3- Protection of Building When used in accordance with Section 4.1.3 of this Certificate, wall lining insulation and separation distances meet the Building Regulation requirements. Part L – Conservation of Fuel and Energy L1 – Conservation of Fuel and Energy The walls and roof of the GOS Insulated Steel Frame Building System can be readily designed to incorporate the required thickness of insulation to meet the Elemental Heat Loss method calculations for walls as recommended in Part L of the Building

Regulations 1997 to 2008 (see Section 4.2 and Table 5). The system can readily be detailed to accommodate a wide variety of plan forms and users of the system must ensure that Building Regulation requirements (avoidance of cold bridging) that are affected by plan form and internal sub-division of the building are complied with. Thermally bridged junctions, when detailed in accordance with this certificate will satisfy the target linear thermal transmittance values as outlined in Table D1 of Appendix D of Part L of the Building Regulations 2007. As a result the improved “y” value of 0.08W/m2K can be achieved and used as the factor for thermal bridging in the DEAP calculations in an assessment of the Building Energy Rating (BER) for dwellings constructed using the GOS Insulated Steel Frame Building System. Part M – Access for People with Disabilities M1 – Access and Use Buildings can be designed to meet the access, circulation and facilities requirements of this Regulation (see Section 4.5 of this Certificate). M2 – Sanitary Conveniences Buildings can be designed to meet the installation requirements for sanitary conveniences for people with disabilities (see Section 4.5 of this Certificate).


Figure 1: Typical Eves Overhang and External Wall Section of the GOS Steel Frame Building System

AIR TIGHT SEAL

SPRAY FOAM

OSB BOARD VAPOUR CONTROL LAYER

NSAI AGRÉMENTAPPROVED CLADDING

FASCIA/SOFFIT TOARCHITECTS SPEC

CONTINUOUS STRIP (25mm WIDE) TO ALLOW WELL

VENTILATED EAVES

EAVES VENTILATOR TO PROVIDE UNOBSTRUCTED

AIR PASSAGE OVER INSULATION

FIRELINE PLASTERBOARD

SOUNDBLOC PLASTERBOARD

11mm OSB 3 BOARD

VAPOUR CONTROL LAYERRIGID FOAM INSULATION

STAINLESS STEEL SLOT AND CHANNEL WITH MASONRY WALL TIE.

MASONRY OUTER LEAF

U-CHORD TRUSS

SERVICE HOLES

BREATHER MEMBRANE

TOP HAT SECTION

COUNTER BATTENS

NSAI AGRÉMENTAPPROVED CLADDING

GOS SPRAY FOAM

FIRE BARRIER

GOS TOP WALL TRACK

GOS STUD

FASCIA / SOFFIT TO ARCHITECTS SPECIFICATION

GOS SPRAY FOAM OMITTED FOR CLARITY

BREATHER MEMBRANE

AIR TIGHT SEAL (BEHIND)

PLASTERBOARD TO SUIT SPECIFICATION (OMITTED)


2.1 PRODUCT DESCRIPTION This Certificate relates to the GOS Insulated Steel Frame Building System for the design, manufacture and erection of cold-formed light gauge steel frame buildings. Buildings using the system are erected on site using a panellised/modular system (factory made and site assembled) with all major custom components being manufactured at GOS Building Solutions production facility. The steel frame walls are pre-insulated in the factory using SealiteTM spray applied polyurethane and rigid foam insulation prior to delivery of the system to site. 2.1.1 Technology The external steel frame panels used in the system are pre-insulated in the factory using SealiteTM spray applied polyurethane insulation. All steel frame panels, which are used on the internal leaf of the brick/block external wall, are injected with spray applied polyurethane insulation within the depth of the cold form section and an additional block of polyisocyanurate (PIR) rigid foam insulation on the cavity side of the cold formed sections as shown in Figure 2. This process allows the external steel frame structure to be kept in a “warmframe” environment. Polyurethane spray insulation is a two component, one-to-one by volume, self-adhering, sealant/air barrier spray. 2.2 GENERAL BUILDING STRUCTURE 2.2.1 Foundations GOS Insulated Steel Frame Building System may be used with a variety of foundation types, depending on the ground conditions encountered on site. A site investigation should be carried out by an appropriately qualified and experienced Chartered Engineer to determine the maximum bearing pressure the soil can carry. Once this is established a suitable foundation type can be selected. A tolerance of ±5mm is specified for either concrete slab or top of rising wall level and horizontal dimensions. Where variations in slab (or rising wall) level occur, such variations are catered for using fibre cement or galvanised steel spacers (shims) located directly below the studs as required. The use of such shims should be kept to a minimum and care must be exercised to prevent damage to the DPM. The remaining gaps below the steel frame panel sole plate are filled using non-shrink grout. Note: The construction of the foundations and ground floor slab are the responsibility of the main contractor, and should be constructed in accordance with the client’s engineering specifications. Due to the low

tolerances of the steel frame manufacture, the foundation and ground floor slab must be constructed accurately, i.e. correct dimensions, square and level so that the steel frame system can be assembled and erected properly within the specified tolerances. 2.2.2 Ground Floor An in-situ concrete slab or a raft foundation may be used to form the ground floor. Below the in-situ concrete slab, insulation is provided in accordance with the requirements of TGD to Part L of the Building Regulations 1997 to 2008 to avoid cold bridging and to contribute to the overall U-value of the building. An NSAI Agrément approved radon resistant membrane is installed in accordance with Clause 8 of IS 325-2:1995 Code of practice for use of masonry – Masonry construction and BS 8102:1990 Code of practice for protection of structures against water from the ground, to protect the floor and bottom channels of the steel studs from rising damp. All joints and service penetrations must be fully sealed. 2.2.3 Concrete Podium Slab (Transfer Slab) Where the GOS Insulated Steel Frame Building System is constructed off a concrete podium slab (transfer slab) the structural design of the substructure should be in accordance with Section 3 of this Certificate. A tolerance of ±5mm is required on the podium slab line and level; procedures for variations in slab are similar to that described in Section 2.2.1. The construction of the podium slab is the responsibility of the main contractor and should be constructed in accordance with the client engineer’s specifications. The design of the podium slab and substructure is the responsibility of the client’s engineer, who will require the information detailed in Section 3 of this Certificate from a GOS Chartered Structural Engineer. GOS Structural Certification is from transfer slab level upwards. 2.2.4 External Cladding The external leaf of the GOS Insulated Steel Frame Building System is generally of traditional brick/block masonry to IS 325-1:1986 Code of practice for use of masonry – Structural use of un-reinforced masonry and IS 325-2:1995 or with other claddings approved by the NSAI Agrément. The masonry outer leaf is tied to the inner leaf with stainless steel dovetailed wall ties which are clipped into the factory fitted stainless steel channel as shown in Figure 1. The channels are factory fitted through the rigid foam insulation with 85mm stainless steel TEC screws directly into the flange of the cold formed studs. The frequency of wall ties shall be as detailed on the GOS construction drawings. An additional tie within a 150mm distance of all opes should be

Part Two / Technical Specification and Control Data 2


provided at a frequency of one per each 225mm of length of opening, movement joint, internal or external corner. The external wall incorporates a minimum clear cavity width in accordance with IS 325. The cavity in the external wall must be maintained and kept clear of construction debris to below DPC level. Masonry claddings must have adequate weep holes along their base. 2.3 STRUCTURAL PRINCIPLES 2.3.1 Steel Frame Structure The basis of the structure is a cold-formed light gauge steel platform frame, which is assembled on site from factory-made panels and loose components fixed using self-drilling/self-tapping screws. The panels are fabricated from suitably coated steel coil, which is formed into the required shapes by proprietary roll-forming equipment. The frequency and size of vertical studs will depend on an individual panels design. Timber or steel roof trusses may be used with the system. The GOS Insulated Steel Frame Building System panels use cold-formed sections as their main structural components. The range of cold formed sections are designed by GOS CAD/CAM software and produced by computer numerically controlled (CNC) fabrication equipment and roll formers. The cold-formed sections used in the building system are manufactured from a minimum grade S350 steel coils. The steel coils are zinc coated (275g/m2) to I.S. EN10326:2004 Continuously Hot-Dip Coated Strip and Sheet of Structural Steels - Technical Delivery Conditions and to I.S. EN 10147: 2000 Continuously Hot-Dip Zinc Coated Structural Steel Strip and Sheet – Technical Delivery Conditions. The grades of steel and dimensions of sections used are selected and specified by a GOS Chartered Structural Design Engineer in accordance with design requirements. Table 1 shows typical specifications for the steel members. Section properties are calculated using design core thickness of steel (excluding coatings) in accordance to BS EN1993-1-3:2006 – Eurocode 3 – Design of Steel Structures – Part 1-3: General Rules – Supplementary Rules For Cold-Formed Members and Sheeting and BS-EN 1993-1-5:2006 Eurocode 3 – Design of Steel structures - Part 1-5: Plated Structural elements. 2.3.2 Load Bearing Walls The gravity loads, i.e. vertical dead and imposed loads are transferred by load bearing external wall panels and if required load bearing internal wall partitions where necessary. The load bearing wall panels are comprised of vertical studs, fixed to horizontal head and bottom channel sections. Horizontal noggins are fitted at the mid-height of all panels where required to

provide additional strength and where particularly high vertical loads occur. Studs can interlock together to form a box sections as required under high concentrated loads. Typically, roof trusses are aligned with the joists, which in turn are aligned above floor studs below. Load transfer is therefore, directly through members. Where this is not possible, for example above window openings, correct load transfer is achieved through lintels (which may be boxed), and additional studs around openings, where necessary. The design loads from each level are transferred through the primary load bearing elements into the substructures/foundations. 2.3.3 Racking Resistance to horizontal loading (racking) is provided by the horizontal diaphragm action of the approved floor sheeting and roof in conjunction with the metal diagonal cross-bracing members on specific external inner leaf and internal walls. All cross bracing is pre-assembled in the factory and has the duel function of ensuring squareness of factory produced panels in addition to providing lateral stability for the overall structure (Figure 2).

Figure 2. Factory assembled cold-formed panel. The roof trusses can be either conventional prefabricated timber roof truss or a GOS cold-formed section truss. Timber roof Trusses are attached to a timber wall plate, which are bolted on site to the top Wall Track of the load bearing GOS wall panel. GOS cold formed roof trusses can be fixed down directly onto the top Wall Track of the load bearing GOS wall panel. Typically roof trusses are aligned with joists, which in turn are aligned above ground floor studs. Load transfer is therefore, directly through members. Where this is not possible, for example above window openings, correct load transfer is achieved through a combination of lintels and additional studs around openings.


2.3.4 Holding Down To provide resistance to uplift, the bottom channel of the external panels are fixed to the ground floor slab, podium slab or rising wall with anchor bolts which have been approved by the NSAI Agrément as being fit for purpose. The type of anchor bolt used to hold down the external panels of the system will be dependent on what substrate the anchor is being fixed to. The positions of the anchors are determined by GOS’s Chartered Structural Engineer and are factory positioned in the bottom channel member. Where anchors are required in the bottom channel of the external insulated panels, factory assembled panels are modified in order to allowed for the installation of

the anchors by leaving a void in the SealiteTM spray applied polyurethane insulation to facilitate installation on site. Figure 9 shows the preferred option of fixing the steel frame bottom channel to a reinforced concrete slab with a proprietary anchor. In addition to the internal leaf of the external wall being fixed to the foundation all internal panels on the ground floor are fixed to the concrete slab with proprietary stainless steel anchors.

Table 1: Typical Sizes of Elements in the Steel Frame System

Typical Section Dimensions Component Type Grade of

Steel Depth (h)

Width (b)

Lip (c)

Thickness1 (t)

Wall Stud S350, S390, S550

70 90

1403

35 42 50

10.8 – 12.5 9.8 – 12.7

10.8 – 13.7

0.8 – 2.0 0.8 – 2.0 0.8 – 2.0

Wall Track/Noggin2 S350, S390, S550

72 – 73.8 92 – 93.8

142 – 143.8

43.2 – 43.7 49.2 – 49.7 58.2 – 58.7

0 0 0

0.8 – 2.0 0.8 – 2.0 0.8 – 2.0

Floor Joist S350, S390, S550

200 250 300

50 50 50

11.7 – 13.8 11.7 – 17.9 13.8 – 17.9

1.5 – 2.0 1.5 – 3.0 2.0 – 3.0

Floor Track2 End Bearer

S350, S390, S550

203.8 – 205 253.8 – 257.5 305 – 307.5

56.7 – 57.1 56.8 – 58.0 57.1 – 58.0

0 0 0

1.5 – 2.0 1.5 – 3.0 2.0 – 3.0

1. The range of thickness of cold formed section available = 0.8, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0mm. 2. Range of Depth (h) and Width (b) available to allow for uniform cross section of structural zone. 3. These profiles are standard; other special profiles are available on request.

Channel with Lip Channel without Lip


Figure 3: Typical Window and Aluminium Cill


GOS STUD

GOS SPRAY FOAM

BREATHER MEMBRANE

RIGID FOAMINSULATION

VAPOUR CONTROL LAYER

STAINLESS STEEL SLOT AND CHANNEL

MASONRY OUTER LEAF

11mm OSB 3 BOARD

FIRE BARRIER

INTERNAL WINDOW BOARD

GOS TRACK

SERVICE HOLES

ALUMINIUM CILL

STEPPED DPC

WINDOW FRAME

STEEL LINTEL

FLEXIBLE SEALANT SILICONESEALANT

COMPRESSIBLE SEAL

DPC RETURNED AT WINDOW JAMB

OSB BOARD VAPOUR CONTROL LAYER FIRELINE PLASTERBOARD


2.3.5 Wall Ties The stainless steel slot and channel cavity wall tie used with the GOS Steel Frame Building System is a proprietary designed system. The tie is intended to be used in masonry to steel studded applications, with a design cavity width of 50mm. The cavity width is defined as the distance between the surface of the rigid foam insulation and the inner surface of the outer masonry leaf. The wall tie system comprises two parts, a factory fitted stainless steel tie channel and a site fitted stainless steel dovetail wall tie. The channel incorporates a slot and is fitted by GOS in production to comply with the requirements of BS DD 140-2:1987 Wall ties – Recommendations for design of wall ties. The tie channels are fitted to the cold-formed steel studs at a frequency which will satisfy the requirements for wall tie spacing as outlined in BS. EN1996-1-1:2005 Eurocode 6 – Design Of Masonry Structures – Part 1-4: General Rules For Reinforced And Unreinforced Masonry Structures. Using this channel system allows for variations within block/brick courses. Around openings, channels are positioned within 150mm of the opening. The slot in the wall tie bracket enables a wall tie to be adjusted vertically for variations in mortar thickness during construction of the masonry outer leaf. Additional wall ties are provided at 225mm centres around all openings, corner and movement joints, such that there is a tie for each 225mm of perimeter of opening or either side of each movement joint/corner. Wall ties are available as standard flat ties and are also available with a twist for installation over window and door opes. The external wall incorporates a minimum clear cavity width in accordance with IS 325. The cavity in the external wall must be maintained and kept clear of construction debris to below DPC level. Masonry claddings must have adequate weep holes along their base and over opes.

Figure 4: Stainless Steel Slot and Channel Wall Tie

The wall ties have been assessed and meet the performance requirements given in BS DD 140-2:1987 for a Type 6 wall tie. The wall tie and channel are made from Grade 304 austenitic stainless steel. The channels are fixed into the cold-formed steel studs

with a self drilling stainless steel screw through the rigid foam insulation directly into the flange of the cold formed studs. 2.4 STEEL FRAME STRUCTURE 2.4.1 External Walls The external walls of a completed building are of cavity construction made up of a pre-insulated steel frame panel inner leaf and an outer external masonry leaf or other approved cladding (ref. Section 2.2.3). The inner leaf panels are pre-insulated in the factory using block of rigid foam insulation on the cavity side of the cold formed sections in conjunction with SealiteTM spray applied polyurethane insulation which fills the voids between the cold formed steel sections in the panels. The standard wall build-up consists of a 90mm deep cold-form stud with spray applied polyurethane insulation in conjunction with 45mm PIR insulation, vapour barrier, internal OSB and plasterboard, which gives the external wall an elemental U-value in accordance with that required by TGD to Part L of the Building Regulations 1997 to 2008. GOS can tailor the external wall build-up to achieve better elemental u-values as requested. A vapour control layer and plasterboard lining to the required specification is then applied to the room face of the pre-insulated steel frame panel on site. The external masonry wall is tied to the inner pre-insulated steel panel using the wall tie system described in Section 2.3.5. The head of external gable walls must be cavity closed in warm roof applications, and closed at ceiling level in cold roof applications. The ground floor panels are fixed by means of anchor bolts as described in Section 2.3.4. 2.4.2 Compartmentation 2.4.2.1 Separating Wall (Party Wall) Separating walls (party walls) are constructed using a minimum of two independent 90/1.2mm cold formed steel framed leaves (studs at 600mm centres max.) with a layer of 11mm OSB 3 board, a central layer of 15mm gypsum soundbloc and a layer of 15mm type 5/F plasterboard internal lining on each side, fixed with the joints staggered. A single layer of semi-rigid mineral wool fibre 70mm thick with a density not less than 10kg/m3 is placed in the 70mm cavity between the adjoining frames of the party wall. The mineral wool fibre is continuous from ground floor to the upper floor ceiling level and adds to the acoustic properties of the wall. Where the attic space is habitable the mineral wool fibre must go up to the underside of the roof. Where the party wall abuts an external wall, the mineral wool within the cavity of the party wall extends through the inner leaf of the external wall and abuts the cavity closer as shown in Figure 7. This detail seals air gaps and minimises flanking sound transmission. At the junction of the compartment floor and the party wall, an additional 300mm section of mineral wool insulation is provided within the cold formed section zone each side of the cavity mineral wool in order to minimise flanking and direct sound transmission. The


head of the party wall must also be fire stopped and cavity closed as specified by the GOS construction details. Where services are required in a party wall, they can be accommodated by additional dry lining to the party wall with battens and plasterboard. Designers must comply with the requirements of section 3.2.5 of TGD B of Building Regulations 1997 to 2008. 2.4.2.2 Single Frame Compartment Walls A compartment wall within the GOS system can be constructed of a single frame wall but this compartment wall must not be used where a wall is common to two or more buildings (separating wall) or where a compartment wall is used to separate domestic apartments from each other within a building. However the single frame panel must be designed and specified to meet the acoustic, fire and structural requirements required by the wall within the building to meet the requirements of the Building Regulations 1997 to 2008. No services are allowed within the compartment wall and where services are required in a compartment wall, they can only be accommodated by battening out the wall similar to accommodating services in a party wall. Services however, can pass through a compartment wall but they must be appropriately protected in accordance with Section 3.4 of TGD to Part B. The build-up of a single framed compartment wall is outlined in table 4 under wall type 4 and should not be confused with wall type 2 on the same table. 2.4.2.3 Compartment Floors The compartment floor used with the GOS Steel Frame Building System consists of 250mm deep cold formed steel joists. The 250mm cold formed sections can be supplied with service opes preformed into the webs of the cold formed sections. The service opes can accommodate the 100mm waste from sanitary services however, every effort should be made to minimise the extent of waste pipes within the compartment floor and wastes should be extended to the outside of the building envelope or to a service riser as efficiently as is possible. Right angle bends should be avoided and rodding point provided. All penetrations must be adequately fire stopped. Electrical installations and recessed lights cannot be accommodated within a compartment floor, a separate false ceiling must be provided by battening out the underside of the compartment floor for such installations and adequate ventilation or other means to prevent overheating must be considered. The floor build up consists of 50mm reinforced screed on a 5mm resilient layer on 22mm plywood supported on the 250mm (min.) deep cold formed sections. The underside of the compartment floor consists of 2 layers of plasterboard over an air tight barrier fixed to the 250mm cold formed joists. 100mm of mineral wool insulation is provided between each cold formed

section. The resilient layer provides acoustic properties to ensure compliance with the requirements of Part E of the Building Regulations 1997 to 2008. For additional acoustic properties in excess of the requirement of TGD to Part E an additional absorbent quilt (10-36kg/m3) can be added between joists. Further improvements to acoustic reductions can be achieved by using resilient bars between the cold formed steel joists and the plaster board. The principles of installation of the cold formed steel joist floor are in accordance with the general principles of installation described in section 2.8.1. Each 22mm sheet of ply is placed such that the joint in the sheets are staggered and each sheet is individually screwed at each cold formed joist location. Further to the compartment floor comprised of cold formed sections, a composite concrete profile metal deck can also be incorporated into the system, where allowed by the structural analysis. The requirements for sound performance as outlined in Diagram 10 of TGD to Part E, namely a minimum average mass of 365kg/m2 must be adhered to. A composite concrete profile metal deck must be designed such that it achieves a minimum of 1hr fire resistance or greater as required by the overall fire strategy drawings for the building. Fire Resistance The cold formed steel joist floor provides 1hr fire resistance from the underside of the 15mm thick gypsum plasterboard on one layers of 15mm Soundbloc gypsum plasterboard on cold formed joists at 600mm centres. All electrical services and wires must be accommodated to the underside of the fire resisting plasterboard. Mechanical Ventilation ducting extraction are allowed within the void of the floor but must be appropriately fire sealed where they enter and exit and comply with the recommendations contained within BS 5588-9:1999 Fire precautions in the design, construction and use of buildings. Code of practice for ventilation and air conditioning ductwork. Where pipes pass through a compartment floor (unless the pipe is in a protected shaft) they should comply with section 3.4.2 of TGD B of Building Regulations 1997 to 2008. The steel joist compartment floor is not suitable for buildings of purpose class 2(a) unless non-combustible material is used in the protection of the floor. Figure 8 illustrates the junction between external masonry clad wall and compartment floor showing cavity barrier and floor build up of steel joist compartment floor.


FLEXIBLE SEALANT

WINDOW SILL TO EXTEND 75mm PAST FACE OF BRICK

FIRELINE PLASTERBOARD VAPOUR CONTROL LAYER OSB BOARD

RIGID FOAM INSULATION

GOS STUD

GOS SPRAY FOAM

BREATHER MEMBRANE



MASONRYOUTER LEAF

11mm OSB 3 BOARD

FIRE BARRIER

DOOR/WINDOW FRAME

Figure 5 – Window/Door Jamb.


2.4.3 Internal Walls Load bearing and non-load bearing internal walls are formed from steel framed panels, similar to those used in the external walls. Load bearing studs are wind braced in production in accordance with the structural design requirements. Steel straps or sheet bracing are used for bracing and are fitted diagonally across the panels. The bracing also assists in keeping the frames square during erection. Non-load bearing infill panels in both internal walls and non-structural external wall panels are detailed to accommodate the natural movement and deflections of the primary structure in which they are installed. In order to eliminate potential loading of non-structural infill panels, deflection heads are provided at the head of the GOS panel. When non-structural external wall panels are subject to horizontal wind loading, specialist advice should be sought from GOS in relation to wind posts and deflection head fixing details. While the provision of deflection head must accommodate vertical movement, installers must take care that the air tightness and acoustic integrity at these junctions is fully maintained though the use of sealant tapes and flexible mastic joints. All load bearing panels must be sufficiently supported directly under the panels with rising blockwork or equivalent. Plasterboard specifications on the steel panels should be in accordance with Table 4 in Section 4, which shows the plasterboard fire resistance requirements for wall, floor and ceiling elements. The plasterboard linings are fixed to the walls and ceilings by means of self-drill/self-tap screws; all joints are then taped and filled. This method of fixing the plasterboard eliminates nail popping. All joints on successive plasterboard layers should be staggered. 2.4.4 Intermediate Floor The intermediate floor consists of galvanised steel joists at 600mm maximum centres fixed to a load bearing partitions, with a minimum covering of 50mm reinforced screed on a 5mm resilient layer on 22mm plywood. Where joists occur at 600mm centres only approved plywood may be used. The floor decking ply is fixed to the floor joists using self-drill/self-tap screws and all splices must occur over the top flange of the galvanised steel joists. In the situation where plywood splices/joints cannot coincide with the galvanised steel joists, secondary timber or cold formed steel grounds must be provided to give suitable support and fixing to these splice locations. The floor joists are typically 250 x 50mm and 1.5 to 3.0mm in thickness, dependant on span. The floor joists should be positioned to coincide with the load bearing stud positions below and must be fixed to the top track using approved self-drilling screws. Web stiffeners are fitted as required for structural stiffness. Floors are not allowed to run through the party wall (separating wall).

2.4.5 Services in Floor Joists The 250mm deep floor joists incorporate circular service holes typically 125mm Ø which are located as required to allow for services to run through the joists. Where additional holes are required in the webs of the joists, advice must be sought from GOS on the positioning of such service holes. All unswaged service holes incorporating services must be lined with a polyethylene grommet or sleeve to avoid the occurrence of damage to plastic pipes or cable sheathing. All service holes are provided at the manufacturing stage in the GOS factory. If additional service opes are required on site, advice must be sought from GOS on a suitable location. The edges to site formed service opes will require protection by the application of a zinc rich paint and lining with lined with a polyethylene grommet. 2.4.6 Ceilings An inner layer of 15mm sound board plasterboard with an outer layer of 15mm type 5/F plasterboard are fixed to the underside of the floor joists using approved zinc plated self drilling drywall screws to the required specification. On the upper floor timber noggins or top hat sections are fixed to the underside of roof trusses to facilitate the fixing of plasterboard. In a cold roof construction a vapour check lining must be provided in accordance with the recommendations of BS 5250:2002 Code of practice for control of condensation in buildings. All ceiling perimeters require a mastic airtight acoustic sealant. A layer of cold formed top hat sections may be necessary when lining the ceiling of prefabricated timber truss roofs in order to ensure a level soffit over the entire ceiling area. 2.4.7 Roof The system can be used with timber or steel roof trusses. The steel roof trusses are erected on site and are supported on the cold formed section top track as shown in figure 1 or as specified by the GOS Chartered Structural Engineer. Steel roof trusses should coincide with the vertical studs of the GOS supporting wall panel. When this is not possible advice should be sought on strengthening of the steel top track. Where timber pre-fabricated roof trusses are used with the system, the roof trusses should be designed and manufactured in accordance with BS 5268-2:2002 Structural use of timber – Code of practice for permissible stress design, materials and workmanship. Timber prefabricated roof trusses are supported on a timber wall plate which in turn is bolted to the top track of the GOS supporting wall panel. In a typical cold roof construction mineral fibre or spray applied insulation of suitable thickness is placed between the ceiling joists. Roofs may be clad with concrete or clay interlocking tiles; NSAI Agrément approved roof sheets or slates imposing a load not exceeding 0.55kN/m2. The tiles/slates are placed on timber or galvanised steel roof battens over an approved roof underlay on a ventilated pitched roof, in accordance with ICP 2:2002 Irish code of practice for slating and tiling and BS


5534:2003 Code of practice for slating and tiling (including shingles). Figure 1 shows a typical eaves detail with fire barrier for a cold roof showing the steel roof truss fixed in position. Other NSAI Agrément approved roofing systems may also be used with the system where specified by GOS. 2.4.8 Chimney Construction GOS Steel Frame Building System can incorporate both traditional block/brick chimney construction or an NSAI Agrément approved pre-fabricated chimney system in accordance with its NSAI Agrément Certificate and the Building Regulations 1997 to 2008. For space separation of heat producing appliances the requirements of TGD to Part J of the Building Regulations 1997 to 2008 should be observed. 2.4.9 Cavity Barriers and Fire Stops To meet the requirements of TGD to Part B of the Building Regulations 1997 to 2008, correctly fitting cavity barriers and fire stops should be provided in the construction of steel frame walls as follows: • The installer should provide cavity barriers around

all openings such as doors, windows, vents extractor fans, meter cupboards, etc.

• Cavity barriers should also be installed at eaves and verges, including detached dwellings.

• In semi-detached and terraced units both cavity barriers and fire stops are fitted at the junction of party walls with external walls.

• The tops of all external cavity walls must be closed as described in Section 3.3.4 of TGD to Part B of the Building Regulations 1997 to 2008.

• Vertical cavity barriers must be detailed similar to party wall/ external wall junctions as shown in figure 7. The cavity barrier must extend the full width of the cavity and inner leaf.

Figures 1-3 and 4-8 show typical details on the correct locations for the installation of cavity barriers and fire stops in the GOS Steel Frame Building System. 2.4.10 Internal Linings and Finishes Linings to walls and ceilings are of plasterboard as specified in Table 4 manufactured to BS 1230-1:1985 Gypsum plasterboard – Specification for plasterboard excluding minerals submitted to secondary operations which are attached by means of self-drill/self-tap screws into steel members. In accordance with good building practice all wall linings in moisture prone areas such as bathroom, kitchen and utility should be lined with foil-backed or moisture resistant plasterboard. Joints in plasterboard wall linings shall be taped and filled in accordance with the plasterboard manufacturer’s instructions for direct decoration. Joints in ceilings can be similarly treated. Alternatively skim coat plaster can be applied. Any wall mounted fitting to the wall other than lightweight items, e.g. framed pictures, television brackets, must be fixed into a vertical stud behind plasterboard using appropriately sized proprietary fixings. The fixings should be appropriate for fixing to light gauge steel.


Figure 6: Typical Door Head



DPC

11mm OSB 3 BOARD

FIRE BARRIER STEEL LINTEL

DOOR FRAME

MASONRY OUTER LEAF

GOS STUD

SPRAY FOAM INSULATION

BREATHER MEMBRANE


DOOR AND TIMBER PANEL

WEEP HOLES



Figure 7: Junction of Party and External Wall (with cavity closer)

SPRAY FOAMINSULATION

GOS STUD

MASONRY OUTER LEAF

VAPOUR CONTROL

CAVITY CLOSER

DPC

MINERAL WOOL FIBRE


BREATHER MEMBRANE


11mm OSB BOARD WITH PLASTERBOARD TO SPECIFICATION


2

Figure 8: Detail at Junction of GOS Cold Formed Floor and External Wall


BREATHER MEMBRANE




DPC

MASONRY OUTER LEAF

11mm OSB 3 BOARD

GOS STUD

FLOOR SCREED TO SPECIFICATION ACOUSTIC/ RESILIENT LAYER TO SPECIFICATION

MINERAL WOOL FIBRE

GOS END BEARER

FIRE BARRIER

PRE PUNCHED SERVICE HOLE



2.5 PROTECTION OF STEELWORK AGAINST CORROSION

2.5.1 Protective Coatings The steel frame members are all coated with a protective zinc-rich metal coating. The steel frame members are manufactured from galvanized coil steel to IS EN 10326: 2004, Continuously Hot-Dip Coated Strip and Sheet of Structural Steels - Technical Delivery Conditions, (min. yield stress 350 N/mm2) with 275 g/m2 zinc protection. All cold formed section properties are calculated using design core thickness of steel (excluding coatings) in accordance to B.S.EN1993-1-3-2006 Eurocode 3 - Design of Steel Structures - Part 1-3 General Rules - supplementary rules for cold-formed members and sheeting and B.S.EN1993-1-5-2006 Eurocode 3 - Design of Steel Structures - Part 1-5 - plated Structural Elements. In additions to the steel members in the system being protected by zinc rich protective coatings, further protection against corrosion and longer design life is given to the steel by providing the following: • The bottom channel on all ground floor steel frame

panels is additionally protected by a 100mm wide DPC from the floor slab.

• The polyisocyanurate rigid foam insulation keeps the steel in a “warmframe” environment, which, in conjunction with the external breathable membrane and internal air tight barrier, prevents the formation of condensation within the wall structure.

• The metal and timber in the roof trusses is kept free from prolonged moisture build up, by means of free air circulation in the roof space, using ventilation methods in accordance with Part F2 of TGD to Part F of the Building Regulations 1997 to 2008.

• Where steel is cut on site or where the coating of the steel becomes damaged, it is protected by the application of a zinc rich paint.

• All fasteners have been assessed and tested for use with the system, to ensure the 60 year design life of the system.

2.5.2 Fasteners and Connection Joints The unique design of the GOS Insulated Steel Frame Building System allows for no welding of joints in the system. The system is assembled using fasteners such as rivets, screws or bolts. All fasteners used in the steel frame system are adequately protected against corrosion i.e. galvanising/zinc coating and made from a suitable metal in order to ensure the design life of the system is maintained. The NSAI Agrément has assessed and approved all fasteners in the GOS Insulated Steel Frame Building System. Testing included humidity cabinet exposure and salt spray/fog tests. GOS provide a full specification of all fasteners, where they are to be used and how they are to be installed during the construction of the system. Only approved system fasteners must be supplied by GOS for use with the system. It is important to ensure that protective coatings on fasteners are not removed, i.e. to assist the fitting of a connection, as this would severely compromise the corrosion performance of the fastener. Where a building is located within one kilometre of the coastline and has a steel roof, all fasteners at the eaves

shall be coated with a zinc rich paint to protect against coastal spray. 2.6 DESIGN AND MANUFACTURE 2.6.1 Design Before a steel frame building can be manufactured a Chartered Structural Engineer must complete the structural design including the specification of all members. The client’s architectural drawings are received by GOS and converted into a 3D structural computer aided design model (CAD/CAM). This system automatically calculates all framing requirements for walls, floors, roof trusses, and allows for all openings such as doors and windows. Each individual frame member is allocated a unique identification number and has its length calculated, along with the position of any cut-outs, punch holes or bracket positions. Before a drawing is transferred to production it is checked and signed off by a GOS Chartered Structural Engineer to ensure structural compliance. Once the drawings have been cleared for production they are transferred to the computer which operates the roll-forming equipment. 2.6.2 Manufacture Roll-Form Production The roll-formers use computer aided manufacturing (CAM) techniques to process the data, which has been transferred from the design office to the roll former. The steel coil is then formed into the required shapes, with the position of cut-outs, punch-holes etc. being accurately located within a tolerance of ±2mm per 10m length. Individual members are grouped into bundles as they come off the roll-forming equipment, corresponding to their subsequent handling in the assembly process. Assembly of the components can commence in the factory directly after it has been roll-formed or the components can be transferred in flat pack form for assembly elsewhere by GOS approved installers. Wall Panel Assembly The steel frame components are composed of galvanised mild steel manufactured from galvanised coil as described in Section 2.5. All profiles are designed in accordance with B.S.EN1993-1-3-2006 Eurocode 3 - Design of Steel Structures - Part 1-3 General Rules - supplementary rules for cold-formed members and sheeting. Section properties comply with BS EN 10162:2003 Cold rolled steel sections – Technical delivery conditions –Dimensional and cross-sectional tolerances. The wall panels have vertical, C-channel studs at maximum 600mm centres, which are fixed to top and bottom horizontal channels using self tapping galvanised steel screws. The screws are precisely located in pre-punched holes in the studs, which match holes in the top and bottom channel. The pre-punched holes in the studs are dimpled which allows the flat topped self tapping galvanised steel screws to be flush with the metal surface. These dimples also mate with the dimples in the horizontal channel, which increase the shear strength of the joint.


2.6.3 Quality Control Production Quality control carried out during manufacture includes visual inspection of steel coiled raw material, calibration of roll forming equipment on a daily basis, cross checking of all in-house production drawings and checks on production dimensions (length, width, and steel thickness) and on the dimensions and squareness of finished panels. Each panel is labelled with a QC sticker confirming it has passed final inspection. In addition to this GOS operate a full in-house quality control system, which outlines procedures on material specification, quality control in production, purchasing of raw materials, design and assembly. The following manufacturing tolerances are observed: Length: ±2mm in 10m lengths Opening position: ±2mm Size of openings: +5mm –0mm Frame squareness: ±2mm Site Erection Site supervision of erection is carried out on a continuous basis by GOS typically at floor slab, wall plate and upon completion of the steel envelope but before the installation of internal dry linings so as to allow the visual checking of all structural and fire stopping elements. 2.7 DELIVERY AND SITE HANDLING 2.7.1 Delivery of Frames The building frame kits can be delivered to site on purpose designed stillages or may be delivered flat packed and strapped. Frames shall be stored on site horizontally or preferably vertically. Frames must be stored on a dry, clean, level base with a suitable packing to prevent damage and must not be dropped or allowed to rest on projecting objects. Care is needed to avoid scratching the surface of the steel frame members or contamination from carbon steel during pick-up. Panels are lifted from the stillages in a sequential manner with a mechanical lifting device. The maximum weight of any single panel should not be more than 200kg. Larger panels will require mechanical lifting. The use of protective gloves when handling frames is strongly recommended, as steel members formed from cut or sheared sheet can have sharp edges and care should be taken when handled to avoid injury. The steel frames must be kept out of contact with dry cement and lime. Flooring and other ancillary items such as insulation and fire stops must also be kept dry and stored on a firm level base. 2.7.2 Typical Material List Supplied to Site With each customised delivery of a GOS Insulated Steel Frame Building System to site, a comprehensive bill of materials is supplied. This bill of materials gives a detailed list of all components delivered. All frame components are individually numbered using the pre-marking system during production to correspond with the erection drawings supplied with the bill of materials. This pre-marking system gives the advantages of both speed and accuracy during assembly and erection on site.

Table 2 gives a typical bill of materials and also include a typical erectors kit. Table 2: Typical Bill of Materials and Erectors Kit Supplied to site Erectors Kit

Wall Panels Full set of erection drawings

DPCs Erection Manual

Floor Joists All connection cleats and hangers

Floor Decking 22mm Ply OSB/3 Plywood, Plasterboard Holding down bolts

Cavity Barriers & Fire Stops Hot wire knife

All Fasteners i.e. Self-Tapping Screws and Holding Down Bolts etc

Spare fasteners

Wall Ties

Acoustic Insulation 2.7.3 Main Contractor The main contractor is responsible for the proper construction of the foundations, ground floor slab or podium slab within the tolerances specified by GOS. Once the floor slab is within the tolerance range, erection of the GOS Insulated Steel Frame Building System can commence. When the steel structure is completely erected brick/block laying trades can commence. The main contractor on site is responsible for providing scaffolding to wall plate level and all access necessary for the safe erection of the structure. GOS also provide the main contractor with project specific building details on the construction of their steel frame system. 2.8 INSTALLATION 2.8.1 General Erection is carried out in accordance with the requirements of this Certificate and all relevant codes of building practice and the manufacturers instructions contained in the GOS Erection Manual, a copy of which must be available on each site. The erection procedure is conventional for buildings of raft design. Site erection must only be carried out by an approved licensed fabricator/erector or by a specialist sub-contractor under the supervision of GOS and in accordance with the GOS Erection Manual. A GOS structural engineer must assess the adequacy of the design for the proposed superstructure of the building system. 2.8.2 Erection The frame panels are delivered to site in packs that can be off-loaded by mechanical means or by hand taking into account the unit weight and dimensions and the distance of lift required and should conform to the requirements of the Safety, Health and Welfare at Work Act 2005. All off-loading and erection should be in accordance with the GOS Method Statement and erection procedures. Erection tools such as spanners and drill bits should be stainless steel to avoid surface contamination.


Table 3: Ancillary Items

Insulation 1/2 lb polyurethane spray foam, SEALITETM Polyurethane spray foam (Local filling of opes, HD bolts) PIR Rigid Foam Insulation Mineral Wool Fibre, density 10kg/m3 to 100kg/m3 Boards Gypsum Fireline Board Knauf Fireshield Board Gypsum Soundbloc Board OSB Plywood Battens and Bars Treated Timber Battens Resilient Bars 1 sided Resilient Bars 2 sided (i.e. top hat) Steel Top Hat Sections Bracing 100/1.2mm Flat Strap 37/1.2mm Flat Strap Membranes Breather Membrane Vapour control layer. Other Products Fire Stop Putty Pads inside socket Polyethylene-sleeved Rockwool strip Cavity Barrier Kraiber Damtec Acoustic Mat or similar approved Regupol 7210C Acoustic Mat Damp Proof Course Rockwool Cavity Barrier. Stainless Steel Slot and Channel wall ties. Approved Fixings.

2.8.3 Supervision The approved steel frame erection contractors are subject to continuous supervision by GOS site inspectors. The following checklist is provided to offer guidance to clients who intend to carry out their own additional site supervision. The items listed are of a general nature and are in addition to all other building requirements. • All components delivered to site comply with the Bill

of Materials. • Components are not damaged and are properly pre-

marked for erection. • The substructure is set out accurately and level

within the tolerance specified by GOS before the wall panels are positioned.

• The steel frame should not be erected unless any inaccuracies in the floor slab have been corrected.

• The ground floor layout is properly marked out. • DPCs and DPMs are correctly installed in

accordance with BS 8102:1990. • Always lay a course of DPC under all ground floor

panels both internally and externally. • Before plasterboard is attached to the OSB lined

steel panels ensure all joins in the air tight barrier are taped and that all service penetrations are fully sealed.

• Panels are in line and plumb and in accordance with the GOS panel layout.

• Rooms are checked for squareness. • All ground floor steel frame panels are correctly

anchored into position in accordance with the erection drawings.

• All insulated wall panels are free from damage after erection and all horizontal and vertical joints are correctly detailed.

• All bottom tracks to be cleaned of construction debris.

• Wall ties are correctly spaced and positioned. • Horizontal DPCs are correctly turned up against the

bottom channel upstands as dry lining proceeds. • Floor joists are installed correctly supported i.e. joists

should always line up with stud under same. • Stiffeners are used with floor joists over all load

bearing floors. • Joints in floor decking occur on the centre line of the

joists and all T&G joints to run perpendicular to the joists. Decking sheet joints must be staggered.

• Floor is protected with a weatherproof cover and screwed at the correct centres i.e. 150mm at openings, edges and 300mm everywhere else.

• Grommets are installed where necessary to service holes according to layout.

• 5mm resilient layer must be turned up 50mm at the perimeter of all rooms and/or at all joint locations in the screed.

• Ensure all bracing is properly tensioned. • When floor joists are continuous over internal load

bearing support walls, ensure continuity of floor plate action through additional fixings through the webs of the end floor tracks or floor studs.

• Cavity barriers and fire stops are installed as specified and in accordance with the Building Regulations 1997 to 2008.

• Roof trusses are installed plumb and according to layout.

• Roof bracing installed where required. • Steel frame at all floor levels is correctly electrically

earthed at one point and all earth returns are connected back to that point.

• Where galvanised steel section is cut or where any damage occurs to the steel frame a coat of zinc rich paint is applied to exposed surfaces.

• All fasteners must be supplied or approved by GOS. • No modification i.e. cutting of the steelwork is

allowed without prior written permission by a GOS Chartered Structural Engineer.

• The use of angle grinders is not allowed on the galvanised steel work.

• Always maintain 70mm cavity between the two leaves of the party wall.

• Absorbent quilt in the cavity in the party wall has been laid horizontally with no gaps.

• Before plasterboard is attached to the OSB lined steel panels, all internal bottom channels must be inspected and swept clear of any debris and all drainage slots in the channels must remain clear.

• When a building is located within one kilometre of the coastline and a cold formed steel roof truss is used, all fasteners at eaves should be coated with suitable zinc rich paint to protect against coastal salt spray.

2.9 INFILL PANEL INSTALLATION


Infill panels can be designed for buildings in two ways: 1. Made To Measure: A GOS engineer takes actual site

measurements of the existing structural frame and design panels to suit.

2. Designed Off Drawings: GOS design panels from the construction drawings with a built-in allowance for site tolerance.

The GOS infill panel is installed on a clean structural slab which has a level tolerance of ±5mm. GOS licensed contractors install the panels. The bottom track of the infill panel is secured to the slab with holding down bolts at the specified locations identified on the GOS drawings. Blocks of insulation are cut out of the wall panels at the holding down bolt locations in the factory using a hot knife. The blocks are retained and are replaced on site upon installation of the holding down bolts; any minor gaps are fully filled with expanding foam. The vapour control layer is then reinstated and a full section of OSB board is fitted across the two adjacent vertical studs either side of the holding down bolt. All vertical and horizontal fire stopping is carried out in accordance with the GOS Technical Manual details.


Figure 9: Typical Holding Down Detail To Raft Foundation

FIRELINE PLASTERBOARD WITH VAPOUR CONTROL LAYER BEHIND

GROUND FLOOR INSULATION

STEEL PLATE AND STAINLESS STEEL

ANCHOR BOLT

FLOOR SCREED

AIR TIGHT SEAL

OSB BOARD

VAPOUR CONTROL

LAYER

BREATHER MEMBRANE



STAINLESS STEEL SLOT AND

CHANNELMASONRY

OUTER LEAF PAVEMENT

BLOCKWORK

GOS STUD

11mm OSB 3 BOARD

RADON BARRIER

SAND BLINDING

COMPACTED HARDCORE

RAFT FOUNDATION

CAVITY FILLED TO GROUND

LEVEL

FLOOR SCREED TO SPECIFICATIONGROUND FLOOR INSULATION

DPC



3.1 CERTIFICATE OF STRUCTURAL COMPLIANCE

A suitably qualified Chartered Structural design engineer must underwrite the structural design of every building designed for the GOS Insulated Steel Frame Building System. Each steel frame house must be accompanied with a structural design certificate of compliance with the requirement of Part A of the Building Regulations 1997 to 2008. This certificate should cover the adequacy of the dimensions and thickness of each element and member making up the steel frame superstructure, and assess the suitability of the interface between the superstructure and the external cladding. The structural certificate of compliance must also confirm that there is sufficient uplift resistance and that there is adequate racking and load bearing capacity to either side of any opening to ensure the stability of the wall. Dwellings designed and constructed in accordance with this Certificate will have adequate strength and stability. Non-Load Bearing Infill Panel Structural Design The light steel panel studs within the infill panel frame are designed to resist their self weight only as well as imposed face wind loading due to the action of wind on the masonry cladding which is tied to the studs using the slot and channel wall tie system. No wall in-plane stability loads shall be induced into the panel. The GOS Infill panel can only be used within reinforced concrete or steel frames that possess their own independent lateral stability systems. Four Storey Structure The design of the substructure is to be the responsibility of the clients’ structural engineer. Before carrying out this design, the clients engineer will need to liase with GOS Structural Engineer, who will provide the following information: - Loading from the GOS Steel frame Structure on the

podium slab, - The permissible deflection of the podium slab structure

under the GOS Steel Frame line loads and the podium slab level loading,

- How the podium structure is to be designed to avoid disproportionate collapse in accordance with section A3 of TGD A of the Building Regulations 1997 to 2008.

It is likely that the podium structure below the GOS Steel Frame will need to be designed as a key element due to the non-continuity of the vertical load bearing elements at the podium slab interface. 3.2 DESIGN LOADS The design of a typical building has been examined by the NSAI Agrément and demonstrates compliance with the following Codes of Practice. In general, the frame and cold formed thin gauged roof truss is design in accordance with B.S.EN1993-1-3-2006 Eurocode 3 - Design of Steel Structures - Part 1-3 General Rules - supplementary rules for cold-formed members and sheeting, and timber roof trusses to BS 5268-3:1998 Structural use of timber – Code of practice for trussed

rafter roofs to support loads in accordance with BS 6399-1:1996 Loading for buildings – Code of practice for dead and imposed loads, BS 6399-2:1997 Loading for buildings – Code of practice for wind loads, and BS 6399-3:1988 Loading for buildings – Code of practice for imposed roof loads. Design snow and wind loads should be based on Diagram 14 and 15 of TGD to Part A of the Building Regulations 1997 to 2008. Non load bearing partitions and walls are designed in conformance with the criteria set out in BS 8200:1985 Code of practice for design of non load bearing external vertical enclosures of buildings and IS EN 10143:1993 Continuously hot-dip metal coated steel sheet and strip tolerances on dimensions and shape. The design loads covered by the calculations were: − Imposed load on floor of 1.5kN/m2 plus an allowance

of 0.32kN/m2 for internal partitions. − Roof imposed loads of 0.60kN/m2 with an allowance

of 0.25kN/m2 distributed load over a loft space with access, along with a concentrated load of 0.9kN point load i.e. water tank.

− Wind loads based on BS 6399-2:1997 with an effective wind speed up to 45m/s.

Greater loads can be accommodated by request. 3.3 STRUCTURAL TESTING Where it is required, structural testing has been used to verify the relevant aspects of the structure where the design falls outside the scope of B.S.EN1993-1-3-2006 Eurocode 3 - Design of Steel Structures 3.4 WIND LOAD Buildings designed in accordance with the GOS Building System Design Manual will have adequate resistance to wind load in areas within the 25m/s maximum 60 minute wind speed contour (as shown in Diagram 15A of TGD to Part A of the Building Regulations 1997 to 2008). For very exposed sites on hills above the general level of the surrounding terrain, the system can be specifically designed to meet the requirements as defined in BS 6399-2:1997. The system can be designed to be used in all locations in Ireland. 3.5 COASTAL SALT SPRAY Where a building is located within one kilometre of the coastline and a GOS cold formed steel roof truss is used, all fasteners located at eaves should be coated with a suitable anti-corrosive coating i.e. zinc rich paint/grease as a precautionary measure against coastal salt spray. 3.6 IMPACT RESISTANCE The interaction of components is such that, if subjected to exceptional impacts causing local failure, the overall stability of the structure will not be dangerously impaired. 3.7 FOUNDATION DESIGN Foundation design must be in accordance with BS 8004:1986 Code of practice for foundations.

Part Three / Design Data 3


4.1 BEHAVIOUR IN RELATION TO FIRE 4.1.1 Fire Resistance Assessment of test results show that buildings constructed using the GOS Steel Frame Building System can meet the Building Regulation requirements in relation to fire resistance as shown in Table 4. The tests have demonstrated the ability of the GOS Insulated Steel Frame Building System to withstand severe fire exposure for a period in excess of that required for compliance with the Building Regulations in terms of fire performance. Tests have been conducted on behalf of GOS to meet fire test requirements of BS 476 and IS EN 1365-1:2000 Fire resistance tests for load bearing elements – Walls and IS EN 1365-2:2000 Fire resistance tests for load bearing elements – Floors and roofs as indicated in Table 4. Plasterboard Installation The proper application of plasterboard to the steel frame members is critical for both fire and sound performance. Attention shall to be given to proper and practical detailing on the part of the designer and a high standard of workmanship on behalf of the contractor. Plasterboard in addition to all cavity barriers and fire stops on all structural and separating walls must be fully checked on site and signed off. 4.1.2 Surface Spread of Flame An external cladding of brick/block has a designated Class 0 surface spread of flame as shown in Table 3. For a more comprehensive list of material and product fire performance ratings, reference should be made to Table A6 of TGD to Part B of the Building Regulations 1997 to 2008. The Classes defined in accordance with BS 476-7:1997 Fire tests on building materials and structures – Method of test to determine the classification of the surface spread of flame of products. Table 3: Surface Spread of Flame Characteristics Material Fire Rating Brickwork/Blockwork Class 0 Timber Boarding Class 3 Internal Plasterboard before decoration Class 0 Slates/Tiles AA 4.1.3 Protection of Building Combustible material e.g. insulation, should be separated from the flue of a masonry chimney by at least 200mm, or at least 40mm from the outer surface of the chimney. Particular details are given in Section 2 and diagrams 2 – 6 of TGD to Part J of the Building Regulations 1997 to 2008. The separation from a heating appliance to combustible wall insulation material should be as per Clause 2.2.2 and Diagram 8 of TGD to Part J of the Building Regulations 1997 to 2008. For chimneys, covered by IS EN 1859:2000 Chimneys – Metal chimneys – Test methods, separation between this product and the external surface of the chimney is

determined in accordance with Clause 2.17 of Part J of the Building Regulations 1997 to 2008. Combustible material in proximity to a constructional hearth must be protected by 250mm of solid concrete or as detailed in Diagram 4 of TGD to Part J of the Building Regulations 1997 to 2008. 4.1.4 Roof Designation All tiles or slates used in the roof in conjunction with the system are designated AA in accordance with TGD to Part B of the Building Regulations 1997 to 2008 (see Table A5 notional designations of roof coverings). Other NSAI Agrément approved roof coverings may also be used with the system under the guidance of a GOS Chartered Engineer. 4.1.5 Cavity Barriers All building designs must incorporate suitable cavity barriers and fire stops in compliance with the requirements of the Building Regulations 1997 to 2008 (ref. Figures 1-3 and 5-8 and Section 2.4.9 of this Certificate). 4.2 THERMAL INSULATION Steel frame construction as detailed in this certificate can be described as ‘warmframe’ construction as insulation is placed both between and outside of the steel studs. The TGD to Part L of the Building Regulations 1997 to 2008 provides guidance on the method for calculating U-values in structures with bridged layer such as the GOS light steel frame constructions. Further guidance on the assessment of complex bridged elements or inhomogeneous elements can be found in IS EN ISO 6946:2007 Building components and building elements – Thermal resistance and thermal transmittance – calculation method and IS EN ISO 10211:2007 Thermal bridges in building construction – Heat flows and surface temperatures –detailed calculation. Insulation layers are bridged by cold formed structural elements and further corrections/ allowances must be made for metal fixings and air tightness. The thermal transmittance or u-value measured in W/m2K for the GOS system with an insulation thickness of 90mm of SealiteTM spray applied polyurethane insulation and 45mm of polyisocyanurate rigid foam insulation on the cavity side of the cold formed sections in conjunction with a brick/block masonry clad external cavity wall (50mm cavity) has been calculated as 0.27W/m2K (ref. Table 5). This meets the elemental U-value requirements of the Building Regulations 1997 to 2008. To ensure the full thermal benefit of the GOS system it is necessary to install peripheral seals around windows and services in order to achieve air tightness. Service lines should be correctly installed to prevent localised air leakage and increased heat loss through floors.

Part Four / Technical Investigations 4


The linear thermal transmittance (ψ) or Psi describes the heat loss associated with junctions and around openings. The GOS system has been assessed and when detailed in accordance with this certificate, these thermally bridged junctions comply with the requirements of Table D1 of appendix D of TGD to Part L of the Building Regulations 1997 to 2008. ‘Ψ’ values for bridged junctions as outlined in table 6 can be used in calculating the ‘y’ factor for a dwelling.

‘Ψ’ values for other junction outside the scope of this certificate should be assessed in accordance with the BRE IP1/06 “Assessing the effects of thermal bridging at junctions and around openings” and BRE Report BR 497 “Conventions for calculating linear thermal transmittance and temperature factors” in accordance with appendix D of TGD to Part L of the Building Regulations 1997 to 2008.

Table 4: Fire Protection Requirements for Wall, Floor and Ceiling Elements

Type Element Test Standard Results

1

Internal Loaded Floor with Gypsum Board – Live Load 1.5 kN/m2

250/1.5mm Steel floor joists at 400mm centres with 100mm mineral wool insulation density 10kg/m3 min. between joists, 22mm ply fixed to top of joists to support 5mm resilient layer and 50mm screed with mesh. Protected on the underside with an inner layer of 15mm type 1 sound check plasterboard tape and jointed and outer layer of 15mm type 5/F gypsum plasterboard fixed with staggered joints again tape and jointed.

BS 476-21:1987 (Method 8)

60 minutes

2 Internal Load Bearing Wall to Include Sockets - 10 kN per stud (Not a compartment wall) Steel C stud walls with first inner layer 11mm OSB 3 board, middle layer 15mm type 1 sound check plasterboard and outer layer (room face) 15mm type 5/F gypsum plasterboard fixed with staggered joints and 75mm of mineral wool fibre, minimum density 100kg/m3, between the steel studs.

BS 476-21:1987 (Method 8)

60 minutes

3 Load Bearing Party Wall 10 kN per stud. Two steel C stud walls with first inner layer 11mm OSB 3 board, middle layer 15mm type 1 sound check plasterboard and outer layers 15mm type 5/F gypsum plasterboard fixed with staggered joints. 75mm of mineral wool fibre, minimum density 100kg/m3 between the two independent steel studs.

BS 476-21:1987 (Method 8)

60 minutes

4 Single Frame Load Bearing Compartment Wall – 10kN per stud. (Not a party wall) Steel C stud walls with first inner layer 11mm OSB 3 board, middle layer 15mm type 1 sound check plasterboard and outer layer 15mm type 5/F gypsum plasterboard fixed with staggered joints and 75mm of mineral wool fibre, minimum density 100kg/m3, between the steel studs. No services.

BS 476-21:1987 (Method 8)

60 minutes

5 Internal Non-Load Bearing Partition Steel C stud with inner layer 11mm OSB 3 board and outer layer of 12.5mm type 5/F gypsum plasterboard on each face and 75mm of mineral wool fibre, minimum density 100kg/m3 between the studs.

BS 476-21:1987 (Method 8)

60 minutes

6 Load Bearing External Wall 30mins 10 kN per stud. Single 90/1.2mm C stud filled with polyurethane spray foam insulation, inner layer 11mm OSB 3 board on vapour control layer and outer layer 12.5mm type 5/F gypsum plasterboard. Side exposed to cavity consists of 45mm PIR rigid insulation and breathable membrane.

BS 476-21:1987 (Method 8)

30 minutes

7 Load Bearing External Wall 60mins 10 kN per stud Single 90/1.2mm C stud filled with polyurethane spray foam insulation, inner layer 11mm OSB 3 board on vapour control layer and outer layer two 12.5mm type 5/F gypsum plasterboard. Side exposed to cavity consists of 45mm PIR rigid insulation and breathable membrane.

BS 476-21:1987 (Method 8)

60 minutes

Table 5: Typical λ-Value W/mK

GOS Steel Frame Building System

Material Conductivity W/mK (λ) SealiteTM spray applied polyurethane insulation 0.041 Polyisocyanurate Rigid Foam insulation 0.023

Table 6: Typical ψ-Value W/mK

Target linear thermal transmittance (ψ) for different types of junctions.

Junction detail in external wall Linear Thermal Transmittance (ψ) (W/mK) Window sill (aluminium) 0.07 Jamb 0.05 Lintel 0.05 Corner (Normal) 0.09 Corner (inverted) -0.05 Party Wall 0.06 Intermediate Floor 0.02 Gable (insulation at ceiling level) 0.17 Eaves (insulation at ceiling level) 0.06 Gable (insulation at rafter level) 0.12 Eaves (insulation at rafter level) 0.07


4.3 CONDENSATION 4.3.1 Interstitial Condensation Walls Calculations under the guidance of BS 5250:2002: Code of practice for control of condensation in buildings have been carried out for all possible wall and roof build up as covered by this certificate. A vapour control layer is provided at the back of the internal OSB/dry lining in order to provide an additional layer of protection against interstitial condensation. The construction of the external panels also keeps the galvanised steel frame members in a “warmframe” environment, which also prolongs the life of the steel. Care must be taken when installing the DPC below the window boards to ensure that any condensation occurring on the window is drained away from the cavity. Under extreme conditions of temperature and humidity, condensation may occur within the cavity however, this will not lead to degradation of the wall or reduce the thermal performance of the wall. Good building practice such as stepped DPC and weep-holes are essential to ensure that moisture within a cavity is deflected to the outside of the building. 4.3.2 Condensation in Roof A breathable vapour control layer should be used over the whole internal roof area. Depending on the design of roof i.e. warm or cold and the roof underlay used, adequate provision for roof ventilation must be made. Roof ventilation should be carried out in accordance with Part F of the Building Regulations 1997 to 2008 and the recommendations of BS 5250:2002, Code of practice for control of condensation in buildings and slates/tiles should be installed in accordance with ICP 2:2002. It is important to ensure that the ventilation is not obstructed by roof insulation and that the recommendations of TGD Part F, diagram 6 are observed and adhered to (i.e. 50mm unobstructed free air space between the roof deck and the insulation. Only NSAI Agrément approved roof tile/slate under-lays should be used in a roof with the system. 4.3.3 Mould Growth and Surface Condensation When assessed against the requirements of TGD part Appendix D, the GOS Building System satisfies the requirements for thermal bridged locations as the temperature factor (fRsi) is greater that 0.75. 4.4 SOUND 4.4.1 Party Wall The acoustic performance of the party wall specified in Section 2.4.2 has been assessed by comparison with acceptable construction details and through adopting best practice at salient junctions in order to minimise the effects of airborne, impact and flanking sound. In respect to party walls (separating wall) an examination was also carried out of the key junctions in the external walls to ensure compliance with the requirements of Part E of the Building Regulations 1997 to 2008. 4.4.2 Floors The acoustic performance of the compartment floor specified in Section 2.4.2 has been assessed by comparison with acceptable construction details and thought adopting best practice at salient junctions in order to minimise the effects of airborne, impact and flanking sound. In respect to compartment floor

(separating floor) an examination was also carried out of the key junctions in the external walls to ensure compliance with the requirements of Part E of the Building Regulations 1997 to 2008. 4.4.3 On Site Testing On site airborne sound insulation tests were also carried out on the GOS Steel Frame Building System. The testing involved airborne sound insulation tests on separating walls between four pairs of rooms in accordance with BS EN ISO 140-4:1998 Acoustics – Measurement of sound insulation in buildings and of building elements – Field measurements of airborne sound insulation between rooms, and impact sound insulation to BS EN ISO 140-7:1998 Acoustics – Measurement of sound insulation in buildings and of building elements – Field measurement of impact sound insulation of floors. The specifications for the separating wall (party wall) shown in Figure 7 achieves airborne sound insulation through the following: • Structural isolation is achieved by leaving a 70mm

cavity between the two frames. • Dense wall linings. One layer of OSB 3 board with

inner layer of 15mm sound check plasterboard and outer layer of 15mm gypsum plasterboard. All Joints between the OSB and plasterboard layer are staggered, taped and filled.

• GOS Building Solutions use a single layer of mineral wool batts 70mm thick with a density not less than 10kg/m3 which are located between the adjoining frames at the party wall. These glass wool batts are continuous from ground floor to the upper floor ceiling level and provide the required acoustic properties.

• Prevention of flanking sound by sealing between the end of the separating wall frames and the outer masonry leaf as shown in Figure 7.

• At the junction of the compartment floor and the party wall, an additional 300mm section of mineral wool fiber insulation is provided within the cold formed section zone each side of the 70mm mineral wool layer in order to minimise flanking and direct sound transmission.

The separating wall (party wall) in the GOS Insulated Steel Frame Building System has been assessed as being capable of providing very good resistance to airborne sound as the wall has achieved measured sound dB reduction well in excess of that recommended in Part E of the Building Regulations 1997 to 2008. Typical field tests have shown a mean value for airborne sound insulation to be in excess of 60dB. It therefore, can be concluded that the party walls when constructed in accordance with Section 2.4.2 meet the requirements of Part E1 of the Building Regulations 1997 to 2008. The acoustic performance of all new builds should be tested as outlined in TGD to Part E of the Building Regulations 1997 to 2008 in order to show compliance with the sound transmission values for both airborne and impact as outlined in table 1 section 4 of TGD to Part E.


4.5 ACCESS FOR PEOPLE WITH DISABILITIES 4.5.1 Access and Use Building designs can accommodate minimum dimensions for doors/corridors/rooms and circulation spaces to provide access for people with disabilities as indicated in Diagrams 5 – 12 of TGD to Part M of the Building Regulations 1997 to 2008. The installation of a passenger lift must be subject to a particular structural/safety design in each case. 4.5.2 Sanitary Conveniences Buildings can be designed to meet the installation requirements for all necessary and special sanitary conveniences for people with disabilities. 4.6 WEATHERTIGHTNESS AND DAMP

PROOFING 4.6.1 Floor Damp Proofing The system has adequate DPCs and DPMs to resist the passage of moisture from the ground. 4.6.2 Roof Cladding Roof coverings and wall claddings will provide adequate weather resistance in all situations covered by Section 3 of this Certificate, when completed in accordance with this Certificate and the manufacturer’s instructions. 4.6.3 External Cladding The external wall with a masonry outer leaf incorporates a 50mm clear cavity which, when correctly constructed with well filled perpends and mortar-free cavity ties, will minimise the risk of water reaching the cavity faces of the inner leaf. For other NSAI Agrément approved wall cladding systems in exposed areas, a water barrier is fixed behind the 25mm (clean) cavity between inner leaf and external cladding, and this minimises the risk of water reaching the inner leaf. Joints, in the insulating lining to the inner leaf, are weatherproofed and any penetrations are sealed. Wind-driven rain, which may cross the cavity under adverse conditions, will be effectively prevented from penetrating the inner leaf. 4.6.4 Windows and Doors This Certificate does not cover the installation or performance of windows and doors. However, the detailing at window and door openings has been assessed and is considered adequate to ensure that water penetration will not occur at these locations assuming conventional window frame profiles and sealing arrangements are used. Figure’s 3, 5 and 6 show typical robust building details that can be used with the system. The windows and doors are supplied and fitted by their manufacturer and are installed to conventionally bridge the cavity and be lug-fixed back to the framed-out opening provision reveal before dry lining commences. A special aluminium sill, which can accommodate the 50mm cavity in the external wall, is used with the windows. This sill should project a minimum 50mm to the outside of the building. Window sills and external thresholds must either be impervious, run the full width of the cavity and be suitably jointed to a horizontal, continuous cavity tray or DPC which is preferably flexible or a cavity tray must be provided under the opening provision. Good attention to detail must be given to

ensuring that when installing the horizontal cavity tray or DPC below an external window board, that provision for any condensation that may occur on the window is deflected into the cavity and away from the steelwork. The windows and doors are made to order by the window manufacturer using the dimensions provided by the GOS design office. 4.6.5 Rain Water Goods Buildings constructed using the GOS Insulated Steel Frame Building System can readily accommodate adequate rainwater gutters and down pipes. 4.7 ELECTRICAL AND PLUMBING SERVICES Electrical and plumbing services are outside the scope of this Certificate. However, in designing and installing these services it is essential that the following procedures are followed and precautions are taken to minimise the risk of long-term damage to the steel frame or the services. • At the design stage it is useful if the positions and

sizes of services can be established in advance, as special holes may be cut in the factory to help with the rapid and economic installation of services. A considerable amount of services are generally required in bathroom, hot press and utility areas.

• In general the steel frame at each floor level must be connected directly onto the main earthing terminal in the main fuse box and all earth connections in the circuit wired back to this point. This measure is necessary to control the flow of electric current to earth without the risk of corrosion of critical structural components. However, the earthing system must be installed in accordance with the National Rules of the Electro Technical Council of Ireland E.T. 101 (current version).

• All unswaged service holes in the steel frame members must be fitted with rubber or plastic grommets to avoid damage to services. To ease the installation of services, particularly electrical cables, these purpose-made rubber or polyethylene grommets form the inner face of the openings. The service holes may alternatively be formed by swaging which is fully rounded to offer a non-sharpened surface to the services. Where plastic coated electrical wiring is in contact with spray applied polyurethane insulation, then the cables must be enclosed in a suitable conduit, e.g. PVC as outlined in the National Rules of the Electro Technical Council of Ireland E.T. 101 (current version).

• Under no circumstances should electrical cables be placed within compartment floors, walls and/or party walls. Walls must be battened out to provide a false service zone in which to distribute electrical services on these fire rated build-ups.

• The enclosure of cold water pipe work within the external wall should be avoided as condensation on the pipe work could lead to wetting of the steel frame with a consequent risk of corrosion. If enclosure is unavoidable, the cold water pipework must be insulated with tubular plastic insulation, which must be accurately cut at junctions and at changes of direction and held firmly in place with adhesive tape.


Where hot water pipework is enclosed in the inner leaf of the wall, contact between copper pipes and the galvanised frame must be avoided by the use of rubber or plastic grommets.

• Under no circumstances should the flange or web of a steel section be notched away thereby weakening the structural performance.

• Additional slots, notches or holes should not be cut through any steel member without the approval of the Chartered Structural Engineer responsible for the overall design of the structure.

4.8 DURABILITY The steel frame structure and wall cladding has been assessed as capable of achieving a minimum design life of 60 years. The steel structure is constructed from steel members having a 275g/m2 Zinc galvanised coating which will provide adequate protection to the steel members. In addition to this, the steel is kept in a “warmframe” environment, which should prolong that life of the steel. The DPC and the galvanising will provide adequate protection to ensure that the bottom channel has a life equal to that of the other frame members. The rigid PIR and mineral wool insulations are durable materials and will remain effective as an insulant for the life of the building. The roof, internal wall and ceiling linings and the outer leaf of the external wall are all constructed from conventional durable materials. Buildings constructed using the GOS Insulated Steel Frame Building System will, when constructed in accordance with GOS Steel Frame Erection Manual and the requirements of this Certificate along with all relevant codes of practice will have design life of at least 60 years in accordance with BS 7543:2003 Guide to durability of buildings and building elements, products and components. 4.9 MAINTENANCE • Maintenance will be required at a level comparable

with that for buildings of traditional construction. The elimination of wet trades in the construction of the inner leaf of external walls reduces drying time and can reduce the incidence of superficial cracking early in the life of the building.

• As the plasterboard is screwed into the steel structure, there is a much less chance of nail popping in plasterwork, which results in less maintenance of plasterwork, than that of a traditionally constructed house.

• Repainting should be carried out in accordance with the relevant recommendations of BS 6150:2006 Painting of buildings – Code of practice. Timber boarding, fascias, soffits etc. where used, should be treated with an appropriate paint system or translucent stain and should be maintained by periodic re-coating using a paint or stain suitable for external applications, applied in accordance with the manufacturer’s instructions.

• The joints in windows and doors may require resealing at approximately 10 year intervals.

4.10 TESTS AND ASSESSMENTS WERE CARRIED

OUT TO DETERMINE THE FOLLOWING

The following is a summary of the tests and assessments which have been carried out on the GOS Insulated Steel Frame Building System: • Structural strength and stability (racking resistance,

load bearing capacity). • Behaviour in relation to fire. • Acoustic performance, resistance to airborne and

impact sound transmission. • Thermal insulation performance incorporating rigid

foam and spray applied polyurethane insulation. • Corrosion of fasteners in normal conditions with a

view to a minimum 60 year design life. • Compatibility with other materials. • Risk of condensation. • Sound • Air tightness 4.10.1 Other Investigations Existing data was examined to assess: • Adequacy of the GOS Building System Erection

Manual. • Weather tightness of building constructed using the

system. • Durability of the system. • Requirements for maintenance. 4.10.2 Production Audits Production audits were carried out at the GOS factory to examine the process of structural design, steel frame fabrication and to assess the adequacy of the methods adopted for quality control. 4.10.3 Site Erection Visits Buildings under construction were visited to assess the practicability of construction (erection) and the adequacy of GOS site supervision arrangements.


5.1 National Standards Authority of Ireland ("NSAI") following consultation with the Irish Agrément Board ("IAB") has assessed the performance and method of installation of the product/process and the quality of the materials used in its manufacture and certifies the product/process to be fit for the use for which it is certified provided that it is manufactured, installed, used and maintained in accordance with the descriptions and specifications set out in this Certificate and in accordance with the manufacturer's instructions and usual trade practice. This Certificate shall remain valid for five years from date of issue so long as:

(a) the specification of the product is unchanged. (b) the Building Regulations 1997 to 2008 and

any other regulation or standard applicable to the product/process, its use or installation remains unchanged.

(c) the product continues to be assessed for the

quality of its manufacture and marking by NSAI Agrément.

(d) no new information becomes available which

in the opinion of the NSAI Agrément, would preclude the granting of the Certificate.

(e) the product or process continues to be

manufactured, installed, used and maintained in accordance with the description, specifications and safety recommendations set out in this certificate.

(f) the registration and/or surveillance fees due

to NSAI Agrément are paid. 5.2 The NSAI Agrément mark and certification

number may only be used on or in relation to product/processes in respect of which a valid Certificate exists. If the Certificate becomes invalid the Certificate holder must not use the NSAI Agrément mark and certification number and must remove them from the products already marked.

5.3 In granting Certification, the NSAI makes no

representation as to; (a) the absence or presence of patent rights

subsisting in the product/process; or (b) the legal right of the Certificate holder to

market, install or maintain the product/process; or

(c) whether individual products have been

manufactured or installed by the Certificate

holder in accordance with the descriptions and specifications set out in this Certificate

5.4 This Certificate does not comprise installation

instructions and does not replace the manufacturer's directions or any professional or trade advice relating to use and installation which may be appropriate.

5.5 Any recommendations contained in this

Certificate relating to the safe use of the certified product/process are preconditions to the validity of the Certificate. However the NSAI does not certify that the manufacture or installation of the certified product or process in accordance with the descriptions and specifications set out in this Certificate will satisfy the requirements of the Safety, Health and Welfare at Work Act. 2005, or of any other current or future common law duty of care owed by the manufacturer or by the Certificate holder.

5.6 The NSAI is not responsible to any person or

body for loss or damage including personal injury arising as a direct or indirect result of the use of this product or process.

5.7 Where reference is made in this Certificate to

any Act of the Oireachtas, Regulation made thereunder, Statutory Instrument, Code of

Practice, National Standards, manufacturer's instructions, or similar publication, it shall be construed as reference to such publication in the form in which it is in force at the date of this Certification.

Part Five / Conditions of Certification 5


This Certificate No. 08/0327 is accordingly granted by the NSAI to GOS Glenbeigh on behalf of the NSAI Agrément. Date of Issue: December 2008 Signed Seán Balfe Director of NSAI Agrément. Readers may check that the status of this Certificate has not changed by contacting NSAI Agrément, NSAI, 1 Swift Square, Santry, Dublin 9, Ireland. Telephone: (01) 807 3800. Fax: (01) 807 3842. www.nsai.ie

The Irish Agrément Board

NSAI Agrément

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