ASD Specification (Volumn 1 Corrigendum)

7/29/2019 ASD Specification (Volumn 1 Corrigendum)

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ANNEX 4

Annex 4 Page 1 of 86 Filename: GSREV4.docCorrigendum GS9304, update 6-May-99 Printed date:

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ARCHITECTURAL SERVICES DEPARTMENT

GENERAL SPECIFICATION FOR BUILDING (1993)

CORRIGENDUM NO. GS9304

(June, 1999)

[ having incorporated corrigendum No.1 , 2 & 3 (Annex 1, 2 & 3)

issued in 1994, 1995 & 1997]

SECTION 1

PRELIMINARIES

Add to Clause

1.02

BSEN European Standard

ISO International Standard

SECTION 2

DEMOLITION, SITE CLEARANCE & ALTERATIONS

(existing) Clause

2.01

Comply with the Building (Demolition works) Regulations Regulations

replace with Comply with all relevant legislation, Codes of Practice and

Practice Notes in connection with demolition works. Particular

attention is drawn to the following :-

Regulations,

Ordinances,

Codes of

Practice &

Practice Notes

(i) Building (Demolition Works) Regulations (Demolition)

(ii) Construction Sites (Safety) Regulations

(iii) Noise Control Ordinance(iv) Air Pollution Control (amendment) Ordinance

(v) Building Planning Regulations

(vi) The Factories and Industrial Undertakings Ordinance

(vii) The Factories and Industrial Undertakings (Lifting

Appliances and Lifting Gear) Regulations

(viii) The Factories and Industrial Undertakings (Noise at

Work) Regulations

(ix) The Factories and Industrial Undertakings (Safety

Officers and Safety Supervisors) Regulations

(x) Air Pollution Control (Construction Dust) Regulations

(xi) The British Standard Code of Practice for Demolition :

BS 6187.

(xii) Building Department Practice Notes Nos. 71 & 75 for

Authorised Persons and Registered Structural

Engineers

(xiii) Building .Department Practice Notes Nos. 4 , 6 & 26

for Registered Contractors


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(existing) Clause

2.03

Report to the SO details of any suspended asbestos containing

materials found during the survey. If required by the SO,

arrange for an Approved Laboratory to take bulk sample for

analysis to determine the content and the type of asbestos.

Asbestos

materials

replace with Before any demolition or alteration work commences, a

registered asbestos consultant shall be appointed to conduct a

thorough investigation of the building for the presence ofasbestos containing material at the premises and submit an

Asbestos Investigation Report and, if asbestos containing

material is found, an Asbestos Abatement Plan to the

Environmental Protection Department at least 28 days before

the asbestos abatement work commences.

Asbestos

materials

When appropriate, a registered asbestos laboratory shall be

appointed to carry out sampling, measurement or analysis of any

suspected asbestos containing material.

Asbestos removal work shall be carried out by a registeredasbestos contractor under the supervision of a registered

asbestos consultant in compliance with relevant legislation and

codes of practice.

If during the course of the general demolition work, hidden

suspected asbestos containing material is found, stop work

immediately and report to the SO.

(existing) Clause

2.04

Submit a statement as to the proposed method and sequence of

demolition if required by the SO. The SO reserves the right to

prohibit any method of execution of the Works which he regardsas unsafe.

Method of

execution

replace with Before commencement of work, submit a method statement to

the SO as to the proposed method and sequence of demolition

of the building and a safety plan which shall cover the risk

assessment and safety measures for such method statement.

The SO reserves the right to prohibit any method of execution

of the Works which he regards as unsafe.

Method of

execution and

safety plan

The method statement shall be prepared in accordance with the

requirements of the Building Department Practice Notes Nos.71 and 75.

Prior to commencement, the method statement including a

demolition plan and demolition sequence written in both

English and Chinese shall be posted in the site office and on

each operation level. The documents shall fully explain the

requirements to site supervisors, operators and workers.

A Competent Person as stated in Clause 8 of the Building

Regulations (Demolition Works) shall have a minimum of 3

years of relevantexperience and shall be specifically appointed

by the Contractor for the direct supervision of demolition works.

Under the safety plan, a part time registered safety officer and a

full time safety supervisor are to be provided. Safety training


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shall be provided to all site supervisors by the contractor.

Drawing information, particularly for unconventional layouts

and special structures, will be made available to the contractor if

possible. The contractor shall state in his method statement if it

is based on such drawings. In the absence of drawings, the SO

may require a detailed structural survey to be carried out and

endorsed by a Registered Structural Engineer (or equivalent) todefine the existing structure and the appropriate method and

sequence of demolition.

No work on site shall be allowed to commence until the

proposed method statement has been accepted and all

precautionary measures, hoardings, covered walkways, and

other requirements are in place.

The contractor shall obtain all necessary permits from the

Highways and Transport Departments.

(existing) Clause

2.28

Cause as little inconvenience as possible to tenants, occupants

or adjoining owners and the public. prevent duct arising by

well watering debris during the works.

Avoidance of

nuisances

replace with Cause as little inconvenience as possible to tenants, occupants,

adjoining owners and the public. Prevent dust arising by

approved dust control methods.

Avoidance of

nuisances

(existing) Clause

2.30

The removal of asbestos containing materials shall be carried

out by an approved specialist contractor.

Asbestos

removal

replace with The removal of asbestos containing materials shall be carried

out by an approved registered asbestos contractor prior to

commencement of general demolition works to avoid

contamination of debris arising from the demolitions.

Asbestos

removal

(existing) Clause

2.42

Comply with all relevant current legislation, Codes of Practice

and guidance notes in connection with asbestos removal works.

Particular attention shall be drawn to the following :-

Legislation,

Codes of

Practice and

Guidance

Notes

(i) Factories and Industrial Undertakings (Asbestos)Special Regulation 1986.

(ii) Factories and Industrial Undertakings (Asbestos)

(Approval of Respiratory Protective Equipment)

Notice.


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(iii) Control of Asbestos at Work - code of Practice

issued by Labour Department.

(iv) Code of Practice on Handling, Transport and

Disposal of Asbestos Wastes issued by

Environmental Protection Department.

(v) Air Pollution Control Ordinance.

(vi) The Protection of Working Health Series - Asbestos

(Issued by Labour Department).(vii) Guide to the Factories and Industrial Undertaking

(Asbestos) Special Regulations.

replace with Comply with all relevant legislation and Codes of Practice

in connection with asbestos removal works. Particular

attention shall be drawn to the following :-

Regulations,

Ordinances

and Codes of

Practice

(Asbestos)

(i) Factories and Industrial Undertakings (Asbestos)

Regulations.

(ii) Air Pollution Control Ordinance.

(iii) Air Pollution Control (Amendment) Ordinance.

(iv) Air Pollution Control (Asbestos) (Administration)

Regulations

(v) Factories and Industrial Undertakings (Asbestos)

(Approval of Respiratory Protective Equipment)

Notice.

(vi) Code of Practice on Handling, Transportation and

Disposal of Asbestos Waste, Environmental

Protection Department, 1993.

(vii) Code of Practice on Asbestos Work using FullContainment or Mini containment methods,

Environmental Protection Department, Hong Kong.

(viii) Code of Practice on Safe Handling of Low Risk

Asbestos-Containing Material, Environmental

Protection Department, Hong Kong.

(ix) Code of Practice on Safe Handling of In-situ

Asbestos-Containing Material, Environmental

Protection Department, Hong Kong.

(x) Code of Practice on Asbestos Work using Glove

Bag Method, Environmental Protection Department,

Hong Kong.

SECTION 3


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EXCAVATION AND EARTHWORK

add Clause

3.01 (ii)

The method of testing of the total sulphate content shall be in

accordance with BS 1377 (as modified in accordance with

GEO Report No. 36 entitled "Methods of Test for Soils in Hong

Kong for Civil Engineering Purposes (Phase 1 Tests). Test

3.5.5.

(existing) Clause

3.01

(viii)

"Special filling material" is to be "general filling material"

capable of passing through a 75mm BS sieve. The material is to

have the following characteristics:

replace with Special filling material is to be general filling material

capable of passing through a 75mm BS sieve. The material

shall be sampled and tested according to BS 1377 (as modified

in accordance with GEO Report No. 36, entitled Methods of

Test for Soils in Hong Kong for Civil Engineering Purposes

(Phase 1 Tests). The material is to have the following

characteristics :

(existing) Clause

3.01

(viii)(a)

Liquid limit is not to exceed 45%. Sample and test to be toBS

1377.

replace with Liquid limit is not to exceed 45%. Sample and test to be to

GEO Report No. 36 Test 2.4.3.

(existing) Clause

3.01

(viii)(b)

Plasticity index is not to exceed 20%. Sample and test to be to

BS 1377.

replace with Plasticity index is not to exceed 20%. Sample and test to be toGEO Report No. 36. Test 2.5.3

(existing) Clause

3.21 (ii)

Determine the maximum dry density and optimum moisture

content in accordance with BS 1377 Test No. 12 or 13 as

directed by the SO. Test each soil type when first used and

thereafter at the same time as every set of field density tests is

carried out or whenever the SO may direct. Unless otherwise

specified, the number of tests required shall be as stated in

Table 3.3. Keep records identifying the soil type and location

in the Works and showing the following information for each

series of tests :

(a) Maximum dry density.

(b) Optimum moisture content.

replace with Determine the maximum dry density and optimum moisture

content in accordance with GEO Report No. 36 "Methods of

Test for Soil in Hong Kong for Civil Engineering Purpose

(Phase 1 Tests)" as follows :-Optimum Moisture Content: GEO Report No. 36 test 4.3.3A, 4.3.3B,

4.3.4A or 4.3.4B whichever is

instructed by the SO.Maximum dry density: GEO Report No. 36 test 4.3.3A, 4.3.3B,

4.3.4A or 4.3.4B whichever as instructed by

the SO.


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Test each soil type when first used and thereafter at the same

time as every set of field density tests is carried out or whenever

the SO may direct. Unless otherwise specified, the number of

tests required shall be as stated in Table 3.3. Keep the records

identifying the soil type and the location within the works.

(existing) Clause

3.21(iii)

Determine the insitu field density and moisture content in

accordance with BS 1377 Test No. 15A or 15B (the sandreplacement method) as directed by the SO to determine the

relative compaction achieved.

replace with Determine the insitu field density and moisture content in

accordance with G.E.O. Report No. 36, test 9.2.1 or 9.2.2 as

directed by the SO to determine the relative compaction

achieved.

(existing) Clause

3.21

(iv)

Determine moisture content in connection with BS compaction

tests by means of a drying-oven. To expedite results, moisture

contents for field density tests may be determined by use of a"Speedy" moisture tester which, however, shall not be used

until it has been calibrated against moisture content tests

carried out in a drying-oven. Submit a calibration chart for

approval before the "Speedy" moisture tester is used.

replace with Determine moisture content in accordance with compaction

tests under GEO Report No. 36 by means of a drying oven. To

expedite results, moisture contents for field density tests may

be determined by use of a "Speedy" moisture tester which,

however, shall not be used until it has been calibrated against

moisture content tests carried out in a drying oven. Submit acalibration chart for approval before the "Speedy" moisture

tester is used.

SECTION 5

PILING WORK

(existing) Clause

5.04 (i)

The theoretical safe ...... exceed 25% of ...... Loading

capacity of

piles

replace with The theoretical safe ...... exceed 25% (20% only for precast

concrete piles) of......

Loading

capacity of

piles


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(existing) Clause

5.04

(iii)

Minimum yield stress with thickness

Steel Specification

Up to and

including

16 mm

Over 16 mm

Up to and

including 40 mm

BS 4360-Grade 43A 275 MPa 265 MPa

BS 4360

-Grade 50B 355 MPa 345 MPa

replace with Clause

5.04

(iii)

Minimum yield stress with thickness

Steel Specification

Up to and

including

16 mm

Over 16 mm

Up to and

including 25mm

Over 25 mm

Up to and

including 40 mm

BS 4360

-Grade 43A 275 MPa 265 MPa 265 MPa

BS 4360

-Grade 50B 355 MPa 345 MPa 345 MPa

BS 4360

-Grade 55C 450 MPa 430 MPa 415 MPa

add Clause

5.08

(vi)

The centres of all driven piles and of all piles deriving their

resistance mainly from friction shall be placed not less than

half the length of the perimeter of the pile or 500 mm,

whichever is the greater, from the site boundary.

(existing) Clause

5.12

Check the energy ......

W = Weight of the ram of the diesel hammer in KN.

Energy output

of diesel

hammers

replace with The use of diesel hammers for percussive piling shall be

prohibited.

Use of diesel

hammer

(existing) Clause5.14

(iii)

If the Hiley .......7.5 mm when hardwood packings at the pilehead and in the dolly are 100 mm thick.

replace with If the Hiley formula is used to calculate the loading capacity of a

pile, the temporary compression of the driving cap (Cc) shall be

taken as not less than 7.5 mm when the total thickness of

hardwood packings at the pile head and in the dolly is 100 mm

or less (refer to clause 5.18 for percussion steel H pile).

(existing) Clause

5.16

(iv)

Do not use a hammer of weight less than 70% of the

weight.....not less than 7.5mm.


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replace with Do not use a hammer of weight less than 50% of the weight of

the pile during the final set, and if a drop hammer is adopted

limit its stroke to not more than 1.2 m. For set calculation in

accordance with Clause 5.14 (iii), the temporary compression of

driving cap thereof (Cc) shall be taken as not less than7.5mm.

If specified, carry out Dynamic Pile Testing or use other

approved means to demonstrate at construction stage that the

maximum tensile stress solely arising from pile driving does notexceed 12 MPa.

(existing) Clause

5.16 (v)

(d)

Supply sample piles ...... Public Works Laboratory for testing

......

replace with Supply sample piles ...... Public Works Laboratory (unless

ordered otherwise by the SO for projects in rural areas) for

testing ......

(existing) Clause

5.18 (i)

Steel sections must comply with the requirement ofBS 4360

Grade 43A or 50B.

Percussion

steel H piles

replace with Steel sections must comply with the requirement ofBS 4360 Grade

43A, 50B or 55C.

Percussion

steel H piles

(existing) Clause

5.18

(iii)

Carry out splicing ...... shall be tested at a rate of one per hundred

joints or part thereof by ultrasonic ......

replace with Carry out splicing ...... shall be testedat a minimum rate of 1%

of the joints for piles of grade 43A, 50B steel and 10% of the

joints for piles of grade 55C steel by ultrasonic ......

(existing) Clause

5.18

only item (i) to (v)

add (vi) Provide one test specimen for every one hundred segments or

part thereof of each section of same thickness from the same

cast. For the purpose of this clause, same thickness means

similar sections with a variation in thickness not exceeding

+ 5 mm, and segment means every length of pile as rolled.

Test specimen shall be taken from sections selected at random

on site by the SO.

Prepare the test specimens to BS18 as directed and

appropriately mark and deliver them to a P.W. Laboratory, as

directed by the SO.

add (vii) Pile of same size but of different grades shall not be used in the

same site.

add (viii) If Hiley Formula is used to calculate the loading capacity of

percussion steel H pile, the temporary compression of the

driving cap(Cc) shall be taken as not less than 5 mm when the

total thickness of hardwood packings at the pile head and in the

dolly is 50 mm or less.

(existing) Clause Carry out site borings ......(54 mm diameter) ......


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5.19 (ii)

replace with Carry out site borings ......(61 mm diameter) ......

(existing) Clause

5.19

(iv)

Sound bedrock is defined as rock mass of at least 5 m thick and

being:

(a) Partially Weathered Rock (PW), having rock content

greater than 90% (PW 90/100) and with Rock QualityDesignation (RQD) greater than 40%; or

(b) Unweathered Rock (UW).

The rock description ....... published by GIS Hong Kong.

replace with Sound bedrock is defined as rock mass of at least 5 m thick and

being Grade III or better rock (as defined in GEOGUIDE 3,

Guide to Rock and Soil Descriptions prepared by

Geotechnical Engineering Office and published by GIS, Hong

Kong) with core recovery greater than 90%.

For design purposes, the average bearing pressure of piles on

sound bedrock shall not exceed the followings:

(a) 3 MPa for Grade III or better rock with core recovery

greater than 90%

(b) 5 MPa for Grade III/II or better rock with core recovery

greater than 90%

(c) 7.5 MPa for Grade II/I or better rock with core recovery

greater than 95%

(existing) Clause

5.19

(v)

The average bearing pressure of piles on sound bedrock shall

not exceed 5 MPa unless otherwise specified.

replace with The average bearing pressure of piles on sound bedrock shall

not exceed 3 MPa unless otherwise specified.

(existing) Clause

5.19

(vi)

When specified, the bearing pressure may be increase up to 7.5

MPa. The sound bedrock in this case shall be of a higher

quality with at least 5 m thick of UW with RQD equal to orgreater than 75%. Notwithstanding item (ii) above, carry out

site borings at all pile locations to determine the founding level

of each individual pile.

replace with When specified, the bearing pressure of piles on sound bedrock

may be increased to a maximum value of 7.5 MPa.

(existing) Clause

5.20

Non-percussion cast in-situ concrete piles are those not

exceeding 600mm diameter formed by boring. The

requirements of Clause 5.17 (i) and (ii) shall apply. Provide

reinforcement as specified.

Non-

percussion

cast in-situ

concrete piles

replace with (i) Non-percussion cast in-situ concrete piles are those not

exceeding 600mm diameter formed by boring. The

Non-

percussion


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requirements of Clause 5.17 (i) and (ii) shall apply. Provide

reinforcement as specified.

(ii) Before the commencement of piling works, install drill holes

whenever necessary, to obtain sufficient information for the

calculations of pile lengths. The position and number of the

drill holes should be agreed with the SO on site. Two copies

of the drill hole logs have to be submitted to the SO.

cast in-situ

concrete piles

(existing) Clause

5.21(v)

Do not use caissons with enlarged base unless otherwise

specified.

replace with The minimum clear working space inside the caisson (i.e.

excluding the lining) shall not be less than 1.8m diameter. Do

not use caissons with enlarged base unless otherwise specified.

(existing) Clause

5.21(vi)

No person shall enter ...... the following:

(a) Caisson shafts : Provide around each shaft suitable

toe boards of 150 mm minimum height and fencing orother barriers not less than 750 mm high to prevent ....

(b) Ventilation of shaft : Provide sufficient .... The

equipment shall be capable of supplying air at a rate

of not less than 25 litres per second. Provide, in

addition....

replace with No person shall enter......the following:

(a) Caisson shafts : Provide around each shaft suitable

toe boards of 200 mm minimum height and fencing

or other barriers to a height of between 900mm and

1150mm to prevent......(b) Ventilation of shaft : Provide sufficient....The

equipment shall be capable of supplying air at a rate

of not less than 25 litres per second per person.

Provide, in addition....

(existing) Clause

5.21(vi)

....(i) Regulations and Code of Practice : Ensure that proper

attention is paid to the appropriate sections of the Hong

Kong Construction Sites (Safety) Regulations, and also to

the Code of Practice for Safety Precautions in theConstruction of .....

replace with ....

(i) Regulations and Code of Practice : Ensure that proper

attention is paid to the appropriate sections of the Hong

Kong Construction Sites (Safety) Regulations, the Code

of Safe Working Practices for Hand-Dug Caissons

published by the Occupation Safety Health Council and also

to the Code of Practice for Safety Precautions in the

Construction of .....

(existing) Clause

5.22 (ii)

Construct piles to the .........to the specified designated position:


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(a) Percussion precast concrete pile )

Percussion precast prestressed tubular )

concrete piles )

Percussion cast in-situ concrete piles )

Percussion steel H piles ) 50mm

Non-percussion cast in-situ concrete Piles )

(b) Large diameter bored piles )Hand-dug caissons ) 75mm

replace with Construct piles to the .........to the specified designated position:

Percussion precast concrete pile )

Percussion precast prestressed tubular )

concrete piles )

Percussion cast in-situ concrete piles ) 75mm

Percussion steel H piles )

Non-percussion cast in-situ concrete piles )

Large diameter bored piles )Hand-dug caissons )

(existing) Clause

5.26 (i)

Backfill pits after ......BS 1377Test No. 12 or 13 as directed by

the SO. Determine the in-situ field density in accordance with

BS 1377Test 15A or 15B as directed by the SO.

Backfilling

replace with Backfill pits after ...... GEO Report No. 36 test no. 4.3.3B or

4.3.4B as directed by the SO. Determine the in-situ field density

in accordance with GEO Report No. 36 Test No. 9.2.1 or 9.2.2

as directed by the SO.

Backfilling

(existing) Clause

5.29

(iv)

Should the estimated ...... in accordance withBS 6089.

replace with Should the estimated ...... in accordance withCS1.

(existing) Clause

5.41(iv)

CAPWAP analysis

When specified, a number of piles under Dynamic Pile Testing

shall be subject to supplementary, rigorous laboratory wave

analysis using the CAPWAP (Case Pile Wave equation Analysis

Programme) or equivalent approved computer programme.

replace with The number of piles under Dynamic Pile Testing shall be as in

the table in Annex F and subject to supplementary, rigorous

laboratory wave analysis using the CAPWAP (Case Pile Wave

equation Analysis Programme) or equivalent approved

computer programme.


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(existing) Annex

F

Type

of pile

Steel H-piles,

Percussive Precast

Concrete Piles

Cast-insitu Concrete

Piles

Tests

Hand-

dug

Caissons

Large

Diameter

Bored Piles

& Barrettes 100

piles

* L/D30

VibrationTest - - - - 10% -

Dynamic

Pile Test

- - - 8% - -

Sonic

Coring

- All piles - - - -

*L = length of pile

D = diameter of pile

replace with Annex

F

Type of

pile

Steel H-piles,

Percussive Precast

Concrete Piles,

Precast PrestressedTubular Concrete

Piles

Cast-insitu Concrete

Piles

Tests

Hand-dug

Caissons

Large

Diameter

Bored

Piles &

Barrettes

100

piles

*

L/D30

Vibration

Test

- - - - 10% -

Dynamic

Pile Test

- - - 8%** - -

Sonic

Coring

- All piles - - - -

*L = length of pile

D = diameter of pile

**7% to be tested under CASE method and 1% to be tested for CAPWAP method

SECTION 6

STRUCTURAL CONCRETE WORK

(existing) 6.01 to 6.13

replace with GeneralClause

6.01 (i)

Falsework is defined as any temporary structure used to support

a permanent structure during erection until the permanent

structure is self-supporting.

Generally

(ii) Traditional formwork is assembled from individual elements

comprising of sheathing material referred in BS5975 and the

backing structure which supports the sheathing.

(iii) Formwork or forms is that section of the temporary works used

to give the required shape, surface finish and support to pouredconcrete. It consists primarily of sheathing material in direct

contact with the concrete and joists or stringers supporting the


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sheathing.

(iv) Permanent formwork or formwork left-in is formwork designed

to remain in position as part of the permanent work.

(v) Notwithstanding any other clause in the GS, the contractor shall

take sole responsibility for the safe transportation, assembly,

erection, maintenance and removal of formwork and falsework.

Design requirementsClause

6.02 (i)

Prior to construction, submit for approval the design,

supporting calculations, working drawings and working

procedures of formwork and falsework in accordance with BS

5975.

Design

submissions

(ii) When specified, submit the design of falsework (including

supports and foundations) and provide certification by an

independent engineer, at various stages, for the adequacy of the

design as well as its proper execution.

Clause

6.03

Design and construct formwork and falsework to withstand the

worst combination of the following without causing bulging or

deflection :

Loadings for

design and

construction

(i) Total weight of formwork, reinforcement and wet concrete.

(ii) Construction loads, including dynamic effects of placing,

compacting and construction traffic.

(iii) Wind loads.

MaterialsClause

6.04 (i)

Props shall be to BS 4074. No timber props and bracings shall

be permitted.

Props &

bracings

(ii) Formwork shall be timber or moulds of other materials against

which the concrete is cast.

Formwork

(iii) Formwork shall not be splitted, or have other defects such as

cracks.

(iv) Formwork ties shall be of a removable type. Formwork

ties

(v) In waterproof concrete any tie through the concrete shall be of a

type with a baffle and shall leave no holes in the concrete.

(vi) Surface retarders shall be of a type which shall not stain or

colour the concrete.

Surface

retarders

(vii) Release agents used on formwork for structures containing

potable water shall be non-toxic and shall not impart a taste to

the water.

release agent

(viii) Release agents containing mineral oil shall not be used. These

include barrier paint, polyurethane varnish, or wax.


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(ix) Release agent used on steel formwork shall contain a rust-

inhibiting agent.

(x) Polystyrene shall not be used as void formers and box-out

material unless permitted by SO.

Void formers

(xi) Wood preservatives in permanent timber formwork shall be to

clause 21.30.

Wood

preservatives

StorageClause

6.05 (i)

Store formwork off the ground on level supports and in a

manner which shall not result in damage or in deformation or in

contamination of the formwork.

Storage of

formwork

(ii) Release agents and surface retarders in sealed containers shall

be properly marked to identify the contents. They shall be

protected from exposure to conditions which may affect the

material. Store materials in accordance with the manufacturers

recommendations and do not use the materials after the

recommended shelf life has expired.

Storage of

release agents

and surface

retarders

Approval Procedures

Clause

6.06 (i)

Prior approval of the SO must be obtained before work proceeds

for casting concrete below ground against sides of excavation.

Work below

ground

(ii) Prior approval from the SO must be obtained before work

proceeds, for size, type and position of any holes, inserts or

fixings by the contractor or his sub-contractor. No part of the

concrete shall be drilled or cut without prior approval of the SO.

Holes, inserts

or fixings

(iii) Prior approval from the SO must be obtained before application

for the use, type and location of surface retarders and release

agents.

Surface

retarders and

release agents(iv) No reinforcement shall be fixed until the formwork has been

inspected and approved by the SO.

Inspection of

formwork

prior to fixing

of

reinforcement

Construction

Clause

6.07 (i)

Scaffolding shall not be used to support formwork or

falsework even under the erection or dismantling process.

Generally

(ii) Cambers shown on drawings relate to the concrete

immediately before the formwork is struck.

Cambers

Clause

6.08 (i)

Falsework shall be carried down to construction which is

sufficiently strong to afford the necessary support without

damage to any portion of the structure. Falsework

supported directly on soil shall not be permitted. Where

necessary, falsework shall be carried down to foundations

or other suitable bases.

Falsework

(ii) Falsework shall be arranged so that it can be readily

dismantled and removed from the cast concrete without

difficulty or damage to the permanent structure. Where

necessary, falsework shall be arranged so that the soffit


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can be retained in position for such period as required by

Clause 6.12/Table 6.1 of the general specifications.

Clause

6.09 (i)

Props shall be of sufficient strength and number and

placed in such a manner that they, adequately and without

excessive deflection, support the loads likely to be

imposed on them.

Props

(ii) Props shall be spaced at no more than 2 m centres in bothdirections and shall be adequately cross-braced.

Clause

6.10(i)

Formwork shall be firmly supported and individual

panels shall be of a rigid nature.

Formwork

(ii) Wall formwork shall at all times be secured so that it will

not be toppled over by wind. Do not leave unsecured wall

formwork in a vertical position.

(iii) The faces and edges of formwork shall be clean and free

of projecting nails.

(iv) Formers for formwork profile, chamfers, splays , rebates

and other features shall be rigidly and firmly fixed to theformwork.

(v) Wood preservatives shall be applied to all surfaces of left

in timber formwork.

Left -in

formwork

(vi) Where the inclination exceeds 15 degrees from the

horizontal, formwork to the top surface shall be provided.

Sloping

formwork

(vii) All joints in formwork including joints between

formwork and completed work shall be closely fitted to

prevent leakage of grout. Gaps, if any, shall be sealed

with gasket, filler, sealant or tape before fixing

reinforcement.

Joints in

formwork

(viii) All joints in formwork shall be tightly secured against

completed work to prevent the formation of stepping or

ridges in the concrete.

(ix) Inserts or box-out to form holes and chases to specified

sizes and shapes shall be fixed in correct positions before

placing concrete.

Forming

holes and

chases

(x) Any device for securing formwork or falsework shall not

be allowed to remain within the specified concrete cover.

Fixing

devices

(xi) Formwork ties and components shall be fixed in such a

manner that they do not touch reinforcement or build-in

component. Any part left in the concrete shall be at least40mm or equivalent to the specified nominal cover to the

reinforcement, whichever is greater.

Formwork

ties and

components

(xii) Formwork ties and components shall be fitted tightly

against formwork faces such that no loss of grout occurs.

(xiii) Unless otherwise permitted by the SO, formwork ties and

components used with profiled formwork shall be a type

such that holes left by the ties and their components are

small enough to be completely located within the recesses

of the concrete surface.

(xiv) Where surface treatment requires bonded adhesion,

release agents shall not be used.

Use of release

agents

(xv) Formwork faces shall be cleaned before release agents

are applied. Concrete, reinforcement and built-in


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components shall not be contaminated by the release

agents.

(xvi) Temporary openings in the formwork for cleaning or

inspection shall be provided if required. Immediately

before concrete is placed in any section of the formwork,

the interior of that section shall be completely cleared of

all extraneous materials including water.

Cleanliness

Removal/ Dismantling of Formwork and FalseworkClause

6.11

Formwork and falsework shall be struck without disturbing,

damaging, or overloading the finished concrete work or the

structure.

Striking

Clause

6.12

Minimum periods for retaining formwork and falsework in

position before striking to be in accordance with Table 6.1.

Minimum

periods

before

striking

TABLE 6.1

Striking time

Type of formwork Concrete without PFA Concrete with

PFA

Vertical formwork to

columns, beams and walls

(unloaded)

24 hrs 30 hrs

Soffit formwork to slabs

(props left under)

3 days 4 days

Props to slabs (unloaded) 7 days 7 days

Soffit formwork to beams

(props left under)

7 days 7 days

Props to beams (unloaded) 16 days 16 days

Props to cantilevers 28 days 28 days

Inclined Formwork to top

surface

12 hrs 12 hrs

(i) These periods are for ordinary Portland cement, at 15Ctemperature. Increase these periods for lower

temperatures as instructed by the SO.

(ii) Where the props are to be left in place whilst the soffit

formwork to slabs and beams is to be removed, such

props shall either be designed to remain in position

throughout the striking process without having to be

temporarily removed or alternatively, if agreed by the SO,

be so designed that a few can be removed at a time and

replaced immediately.

(iii) Do not place construction loads on any unshored portionof the structure under construction. The number of floors

requiring propping is to be as instructed by the SO


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according to the design loads of such floors.

Clause

6.13

NOT USED

(existing) Clause

6.14

Steel reinforcement to be plain round steel bars....type 2 bond

classification to BS 4449 or hard drawn steel wire fabric toBS

4483.

Steel

reinforcement

replace with Steel reinforcement to be plain round steel or deformed high

yield steel bars to CS2 or hard drawn steel wire fabric to BS

4483.

Steel

reinforcement

(existing) Clause

6.15

Obtain steel reinforcement from suppliers who must be able to

produce certificate of routine testing showing the place of

origin and the routine test results for each consignment of steel

reinforcement supplied to site.

Test

certificate

replace with Obtain steel reinforcement from suppliers who must be able to

produce certificates for each consignment of steel reinforcement

supplied to site. The certificates to be submitted shall be inaccordance with the class of reinforcement delivered to site, all

as detailed in CS2.

Test

certificate

(existing) Clause

6.17

Provide and cut..... and rebend tests as required by BS 4449,

appropriately mark and ....

Alternatively the Contractor may, with the permission of the SO,

deliver test specimens to the laboratories of the following

institutions for testing:-

(i) University of Hong Kong

(ii) Hong Kong Polytechnic

Test certificates are to be sent to .....LaboratoriesAllow sufficient.......by the SO.

Test

specimens

replace with Provide and cut test specimens from each consignment as

directed by the SO for tensile tests, bend tests and rebend tests

as required by CS2, appropriately marked and delivered to PW

Laboratory for testing. No claim in respect of steel suffering

from damage or rod lengths being reduced due to the taking of

testing specimens will be entertained.

Alternatively the Contractor may deliver test specimens to the

laboratories approved by the SO.

Test certificates are to be sent to the SO directly from these

Laboratories.

Allow sufficient time......by the SO.

Test

specimens


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(existing) Clause

6.27

Ordinary and ......BS 12 : 1989. Cement

replace with Ordinary and ...... BS 12. Cement

(existing) Clause

6.42

.....

For liquid retaining structures, the minimum cementitious

content shall be 320 Kg/m

3

when the nominal......cement ratiobelow 0.5.

replace with ....

For liquid retaining structures, the design of the concrete mix

shall satisfy the following requirement:-

(i) Maximum Water/Cement ratio to be 0.45.

(ii) Minimum cementitious content to be 325 Kg/m3 .

(iii) Maximum cementitious content to be 400 Kg/m3 .

(iv) Slump should be greater than 75 mm.

(existing) Clause

6.42

TABLE 6.8

Minimum cementitious content (kg/m) and

maximum free water cement (W/C) ratio

Exposure Maximum

Plain concrete Reinforced concrete and

prestressed concrete

conditions aggregate

size

(mm)

Minimum

cementitious

content

Maximum

free W/C

ratio

Minimum

cementitious

content

Maximum

free W/C

ratio

Moderate 40 245 270

20 275 0.65 300 0.60

10 315 340

Severe 40 270 295

20 300 0.60 325 0.55

10 340 365

replace with Clause

6.42

TABLE 6.8

Minimum cementitious content (kg/m) and

maximum free water cement (W/C) ratio

Exposure MaximumPlain concrete Reinforced concrete and

prestressed concrete

conditions aggregate

size

(mm)

Minimum

cementitious

content

Maximum

free W/C

ratio

Minimum

cementitious

content

Maximum

free W/C

ratio

Moderate 40 245 300

20 275 0.65 300 0.60

10 315 340

Severe 40 270 300

20 300 0.60 325 0.55

10 340 365


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(existing) Clause

6.45

TABLE 6.9

Chloride content

Type of concrete

Maximum total chloride

content %

Prestressed concrete

Steam cured structural concrete

0.1

Reinforced concrete

Concrete with embedded metal

0.35

replace with Clause

6.45

TABLE 6.9

Chloride content

Type of concrete

Maximum total chloride

content %

Prestressed concrete

Steam cured structural concrete

0.1

Reinforced concrete made with

sulphate resisting Portland

cement

0.2

Reinforced concrete

Concrete with embedded metal

0.35

(existing) Clause

6.55

item (ii) (a)(b)

add (ii) (c) If the difference between the compressive strengths of

two test cubes made from one sample of designed mix

concrete exceeds 15% of the test result :

(i) the higher of the compressive strengths of the two test

cubes shall be used to assess compliance in Column

B of Table 6.12, and

(ii) the test result for that sample shall not be used to

assess compliance in Column A of Table 6.12 and

shall not be used to calculate the standard deviation.

(existing) Clause

6.55(iv)

When the calculated standard deviation ...... any

subsequent standard deviation calculation.

replace with If the standard deviation of a set of 40 consecutive test

results of concrete judged by the same compliance

criteria exceeds 5 MPa and does not exceed 8 MPa,

compliance requirement C1 shall apply to subsequent test

results. If the standard deviation exceeds 8 MPa, no

further concrete shall be placed in the permanent work

until an investigation of the materials, mix design,

methods of production, sampling and testing has been

carried out and measures have been taken which in the

opinion of the SO will result in restoring a satisfactory

standard of quality control.

add Clause If the compliance requirements are changed from C1 to C2 or


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6.55 (v) from C2 to C1, the new compliance requirements shall apply

from the 35th day after making the last pair of test cubes in the

set of 40 on which the decision to change was based. For the

purpose of calculating the average of any 4 consecutive test

results, test results immediately before and immediately after the

change shall be treated separately.


item (v)

change item (vi)

(existing) Clause

6.55

item (vi)

change item (vii)

add Clause

6.55

(viii)

If designed mix concrete is considered as not complying with

the specified requirements for compressive strength, the SO may

instruct that tests as stated in Clauses 6.57 to 6.59 be carried out

on concrete cores or on samples taken from the hardened

concrete.

(existing) Clause

6.57 (ii)

The average estimated ...... in accordance withBS 6089 ......

replace with The average estimated ...... in accordance with CS 1 ......

(existing) Clause

6.58

Appropriately mark and deliver all concrete cubes and cores to

a PW Laboratory, as directed by the SO.

Testing and

test record

replace with Appropriately mark and deliver all concrete cubes and cores to a

PW Laboratory, unless ordered by the SO for projects in rural

areas.

Testing and

test record

(existing) Clause

6.63

Concrete for water tanks shall comply with the requirements in

Clause 6.43. Where no predetermined construction joints are

specified,.....

Water tanks

replace with Concrete for water tanks shall comply with the requirements in

Clause 6.42. Where no predetermined construction joints are

specified,.....

Water tanks

SECTION 8

CONCRETE FOR MINOR AND

NON-STRUCTURAL WORK

(existing) Clause

8.03

Ordinary Portland cement shall be to BS 12 : 1989.

replace with Ordinary Portland cement shall be to BS 12.


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SECTION 9

BRICK WORK AND BLOCK WORK

(existing) Clause

9.05

Fire bricks to be imported fire clay refractionary bricks of

specified class to BS 1758, of the best quality, light in colour,

uniform in texture and of standard sizes to BS 3056. Testing, if

specified shall be toBS 1902

Fire bricks

replace with Fire bricks to be imported fire clay refractionary bricks ofspecified class of the best quality, light in colour, uniform in

texture and of standard sizes to BS 3056. Testing, if specified

shall be to BS 1902

Fire bricks

(existing) Clause

9.13

Damp proof courses to be 2 layers of 2 layers of 2-ply

bituminous paper or of other types to BS 743. Do not use

hessian based types of bitumen damp proof courses.

Damp proof

course

replace with Damp proof courses to be 2 layers of 2-ply bituminous paper or

of other types to BS 743. Do not use hessian based types of

bitumen damp proof courses.

Damp proof

course

SECTION 10

MASONRY

(existing) Clause

10.01

Stone, generally, to be imported/local granite, of consistent

colour, free from defects that will adversely affect strength or

appearance and complyBS 5390.

Stone

replace with Stone, generally, to be imported/local granite, of consistent

colour, free from defects and ferrous materials that will

adversely affect strength or appearance and comply BS 5390.

Stone

(existing) Clause

10.05

Ties between walls and concrete to be copper or bronze not less

than 40mm wide, 3mm thick and 150mm long and fanged both

ends.

Wall ties

replace with Ties between walls and concrete to be copper, bronze or

stainless steel to BS 1243 not less than 40mm wide, 3mm thick

and 150 mm long and fanged both ends.

Wall ties

(existing) Clause

10.09(b)

Square rubble - Trim stones roughly square 75 to 300mm high,

varying in 75mm stages. Each stone to be 100 to 150mm deepand 100 to 600mm long on bed. Length or depth on bed of each

stone to be greater than the height.

replace with Square uncoursed rubble - Trim stones roughly square 75 to

300mm high, varying in 75mm stages. Each stone to be 100 to

150mm deep and 100 to 600mm long on bed. Length or depth

on bed of each stone to be greater than the height


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(existing) Clause

10.15

Where squared rubble walls exceed 300mm think Square rubble

exceeding

300mm thick

replace with Lay square rubble walls in random sizes (see diagram) where

walls exceed 300mm thick.

Square

rubble walls

Additional

Clause

Clause

10.15A

Lay roughly hammer pitched stones with no pronounced

lamination, to irregular polygonal shapes, and bedded to showthe joints running in all directions (see diagram F & G).

Polygonal

rubblewalling or

Kentish

Rag.


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SECTION 11


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TANKING

(existing) Clause

11.02

For asphalt tanking, the work ....................... Specialist

contractor

replace with For sheet membrane tanking, the work shall be executed by the

manufacturers approved specialist contractor.

Specialist

contractor

SECTION 12

ROOFING

(existing) Clause

12.51

All asphalt roofing for repair works to existing asphalt roofs

shall be laid and executed complete by an approval contractor

on the LWB List for Asphalt Roofing and Tanking.

replace with All asphalt roofing for repair works to existing asphalt roofs

shall be laid and executed complete by an approved contractor

for Asphalt Roofing and Tanking.

(existing) Clause

12.75

4th line : ......... electro-planted.........

replace with ...... electro-plated ......

(existing) Clause

12.79

Fix to steelworks with self tapping screws designed for fixing to

steel. Fix to timber....

Fixing

sheeting

replace with Fix to steelworks with stainless steel self tapping screws

designed for fixing to steel. Fix to timber....

Fixing

sheeting

(existing) Clause

12.80

Cut, fit and dress steel sheet accessories to fit corrugations or

profiles. Where possible, fix with same fixings that secure the

sheeting. Elsewhere, fix to the sheeting with roofing bolts.

Fixing

accessories

replace with Cut, fit and dress steel sheet accessories to fit corrugations or

profiles and fix with approved fixings in accordance with the

manufacturers recommendations.

Fixing

accessories

additional Clause

12.83A

Treat joints of steel corrugated sheet roof according to Clause

12.34.

Waterproof

joints of steelsheet roofing

(existing) Clause

12.99

3rd line : ......... Approved Specialist Roofing Materials

Contractors .........

replace with ......... Acceptable Specialist Roofing Materials/Applicators

(existing) Clause

12.100

2nd line : ......... approved .........

replace with ......... acceptable .........


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SECTION 13

CARPENTRY AND JOINERY

(existing) Clause

13.21

Laminated plastic sheet to BS 438. Class HG (Horizontal-

General Purpose) or VG (Vertical-General Purpose) as

specified.

Laminated

plastic

replace with Laminated plastic sheet to BSEN 438. Class HG (Horizontal-

General Purpose) or VG (Vertical-General Purpose) as

specified.

Laminated

plastic

sheet

(existing) Clause

13.23

The suspension system shall be an approved proprietary system

meeting the requirement of CP 290 manufactured from one of

the following materials.

(i) Galvanised mild steel.

(ii) Aluminium.

(iii) A combination of galvanised mild steel and aluminium.

Proprietary

suspended

ceiling

systems

replace with The suspension system shall be an approved proprietary systemmeeting the requirements ofCP 290 manufactured from one of

the following materials.

(i) Galvanised mild steel.

(ii) Aluminium.

(iii) A combination of galvanised mild steel and aluminium.

Proprietarysuspended

ceiling

systems

(existing) Clause

13.50

Ensure the base is clean and dry. Lay blocks on one coat of an

approved cold bitumen rubber emulsion adhesive applied to the

screed with a serrated trowel. Leave flooring ready to receive

sealer or polish. Sand surface of parquet flooring as Clause13.50.

Parquet

flooring

replace with Ensure the base is clean and dry. Lay blocks on one coat of an

approved cold bitumen rubber emulsion adhesive applied to the

screed with a serrated trowel. Leave flooring ready to receive

sealer or polish. Sand surface of parquet flooring as Clause

13.49.

Parquet

flooring

page 233 Clause

13.57

sub-para (ii) should read Clause 13.56.

SECTION 14IRONMONGERY

Clause

14.35

sub-para. (j) penultimate line should read in pre-bored.

Clause

14.36

first line should read fittings shall be.

SECTION 15


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STRUCTURAL STEEL WORK

(existing) Clause

15.03

Structural steelwork shall comprise weldable structural steel to

BS 4360 grade 43A (mild steel) or grade 50B (high yield steel).

Mechanical

properties and

chemical

composition

replace with Structural steelwork shall comprise weldable structural steel toBS 4360 grade 43A, grade 43C or 43D(for hollow section only)

or grade 50 B.

The use of weldable cold - formed structural hollow sections

shall comply with BS 5950 Part 5, BS 5950 Part 7 andBS 6363.

Mechanicalproperties

and chemical

composition

(existing) Clause

15.22

Carry out welding in accordance with the requirements ofBS

5135. Welding to be manual metal-arc welding unless

otherwise specified.

Welding

replace with Welding shall be a metal arc process in accordance withBS5135 together with other clauses contained in the GS, unless

otherwise specified.

Welding consumables used shall be chosen to ensure that the

mechanical properties of the weld metal are not less than those

required for the parent metal.

Welding

(existing) Clause

15.23

Provide an experienced and competent operator to supervise

welding. Submit certificates proving that all welders have

passed the training tests inBS 1295 and if specified, carry out

approval tests to BS 4871:Pt.1 or BS 4872 : Pt. 1 as

applicable.

Welders and

testing of

welders

replace with Provide an experienced and competent operator to supervise

welding. Welders shall be tested to meet the requirements of

BSEN287 Part 1 but, in the case of welders engaged on fillet

welding only, BS4872 Part 2 is an acceptable alternative.

Test on welders shall be witnessed by a qualified welding

inspector and certificates endorsed by an independent inspection

authority. The certification shall remain valid providing it

complies with the conditions for re-approval of certificationspecified in BSEN 287 Part 1.

Welders and

testing of

welders

(existing) Clause

15.25

Obtain approval of the proposed welding procedures prior to

commencing welding including:

(i) Preparation of fusion faces.

(ii) Preheating temperature where required.

(iii) Type of electrodes.

(iv) Number and sequence of runs to build-up the weld

bead.

(v) Post-heating treatment if required.Do not depart from the agreed welding procedure without the

prior agreement of the SO.

Welding

procedures


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replace with Submit welding procedures which are to be prepared and

certified by a qualified welding inspector. Obtain approval of

the proposed welding procedures prior to commencing welding

including:

(i) Welding process or processes when more than one is

used in making a complete joint,

(ii) Parent metal specification, thickness and other relevantdimensions,

(iii) Classification, type and size of electrodes and other

consumables,

(iv) Welding current, arc voltage and welding speed,

(v) Sketch showing edge preparation, fit-up and

approximate number and arrangement of runs in multi-

run welds,

(vi) Minimum preheating temperature and interpass

temperature range,

(vii) Post-weld heat treatment if required.

Do not depart from the agreed welding procedure without prior

agreement of the SO.

Welding

procedures

(existing) Clause

15.26

Carry out approval ...... BS 4870 :Pt. 1 when specified ...... Approval

testing of

welding

replace with Carry out approval ...... BSEN 288-3 when specified ...... Approval

testing of

welding

(existing) Clause

15.35

Where specified, test welded joints by radiographic methods to

BS 2600 :Pt. 1 and Pt. 2 with the type of film specified by the

SO or by ultrasonic methods to BS 3923 :Pt. 1 and Pt. 2 to

ascertain that the joint is free from flaw, cracks or other

imperfections. Employ an approved specialist firm to carry out

and interpret these tests and provide any necessary labour and

attendance. The testing programme and the standard of

acceptance shall be approved. Should test results indicate that

welds are below the standard of acceptance, carry out approved

remedial measures and further acceptance tests.

Acceptance of

welds

replace with Employ an approved specialist firm to carry out and interpret

the inspection and testing, and provide any necessary labour and

attendance. Submit evidence proving that operators carrying

out the inspection and testing have been trained and assessed for

competence in the inspection and testing of welds. In addition,

submit certificates of competence from a recognised authority

for operators carrying out ultrasonic examination.

Submit testing programme for the approval of SO. Any weldswhich will be rendered inaccessible by subsequent work shall be

examined prior to the loss of access.

Acceptance of

welds


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All welds shall be visually inspected in accordance with

BS5289. Non-destructive testing shall be carried out after

visual inspection in accordance with the table below :

Weld Type Frequency of Non-destructive Testing

All types of butt

welds

100% ultrasonic examination

and magnetic particle flaw detection

Fillet welds with leglength exceeding

and including

10mm

20% ultrasonic examinationand magnetic particle flaw detection

Fillet welds with leg

length not

exceeding 10mm

20% magnetic particle flaw detection

Secondary

attachment welds,

e.g. for fixing

purlins, side rails

5% of attachments by magnetic particle

flaw detection and ultrasonic examination

if leg length exceeds and includes 10mm

The standard of acceptance for butt welds shall be in

accordance with Table 18 quality category A ofBS5135. The

standard of acceptance for fillet welds and secondary

attachment welds shall be in accordance with Table 2 in the

Appendix of the Practice Note for Authorized Persons and

Registered Structural Engineers PNAP 160.

Ultrasonic examination shall be carried out in accordance with

BS3923: Part 1 Level 2B. Magnetic particle flaw detection

shall be carried out in accordance with BS6072. Examinationshall be carried out not less than 16 hours from the time of

completion of the weld to be inspected, or not less than 40 hours

in the case of butt welds thicker than 40mm or any welds to

Grade 55 steels.

Should test results indicate that welds are below the standard of

acceptance, carry out at the Contractors own expense approved

remedial measures and further acceptance tests.

(existing) Clause

15.39

Apply hot dip galvanized coatings ...... as specified in the

contract.

Hot dip

galvanizing

replace with Prior to galvanizing, the following requirements have to be

satisfied :

Hot dip

galvanizing

(i) All welding slags and paints on the steel surface shall be

removed.

(ii) All cut surfaces shall be ground smooth.

(iii) Adequate number of vent holes shall be provided for

closed end hollow sections, and

(iv) Drainage holes shall be provided at joints where free flowof molten zinc would otherwise be impossible, e.g. joints

between stiffeners and I sections.


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Apply hot dip galvanized coatings ...... as specified in the

contract.

(existing) Table

15.3

Type A Primer: Lead based primer toBS 2523 or

drying oil based zinc phosphate

primer

replace with Type A Primer: Drying oil based zinc phosphate

primer

(existing) Table

15.3

Type B Primer: Lead based primer toBS 2523 or

drying oil based zinc phosphate

primer

replace with Type B Primer: Drying oil based zinc phosphate

primer

SECTION 16

CURTAIN WALLS

(existing) Clause

16.47

(iii)(a)

Perpendicular to the plane of the wall, net deflection from

framing members

replace with Perpendicular to the plane of the wall, net deflection of framing

members

SECTION 17

METALWORK

(existing) Clause

17.06

Cast iron to be grey cast iron to BS 1452 Grade 150. Cast Iron

replace with Cast iron to be grey cast iron to BS 1561 Grade 150. Cast Iron

(existing) Clause

17.07

Aluminium alloy plate, sheet and strip to be to BS 1470, of the

required alloy designation.

Aluminium

alloy

replace with Aluminium alloy plate, sheet and strip to be to BSEN 485, 515,573, of the required alloy designation.

Aluminiumalloy

(existing) Clause

17.08

Brass rods and sections to be to BS 2874 designation CZ 106

condition M.

Brass rods

and sections

replace with Brass rods and sections to be to BSEN 12163, 12164, 12167

designation CZ 106 condition M.

Brass rods

and sections

(existing) Clause

17.18

Welding of stainless .......................... subject to approval. Welding of

stainless steel

replace with Welding of steel to be by manual metal-arc welding to BS 5135.Welding of stainless steel to be inert-gas arc welding to BS

7475 or other method subject to approval.

Welding ofstainless steel


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(existing) Clause

17.21

(c)

Zinc sprayed coating to be to BS 2569: Part 1 - nominal

thickness 0.2 mm unless otherwise specified.

Finishes to

steel

replace with Zinc sprayed coating to be to BSEN 22063: Part 1 - nominal

thickness 0.2 mm unless otherwise specified.

Finishes to

steel


(d)

Galvanising to be .............................................. if required.

replace with Galvanising to be hot-dip galvanising to BS 729 with a

minimum thickness of 85 m. Components to be galvanised

after fabrication, if required.

(existing) Clause

17.32

Steel windows and .............................................. in accordance

with the following :-

Steel windows

and doors

(a) Unless otherwise .......................................... prior to delivery to

Site.

replace with Steel windows and doors shall be constructed to BS 6510 and inaccordance with the following :-

(a) When fixed in position, windows and doors shall be designed to

withstand a wind load calculated in accordance with the Code

of Practice on Wind Effects, Hong Kong with a minimum

pressure of 3 kPa and a permissible maximum deflection of

1/180th of the length of the member under consideration.

Calculations are required to be submitted for approval.

(existing) Clause

17.32

(n) When specified, ................................................ and closing

high windows.replace with (n) When specified, high openable windows in inaccessible

locations to be fitted with remote control gear.

(existing) Clause

17.33

Aluminium windows and doors shall be obtained from a

manufacturer on the LWB List for Aluminium Windows, Doors

and Flyscreens and constructed in accordance with the

following: -

Aluminium

windows and

doors

replace with Aluminium windows and doors shall be obtained from a

approval manufacturer and construction in accordance with the

following: -

Aluminium

windows and

doors

(existing) Clause

17.33

(a) When fixed in position ................................................

brackets, etc. as stiffeners..

replace with (a) When fixed in position, windows and doors shall be

designed to withstand a wind load calculated in

accordance with the Code of Practice on Wind Effects,

Hong Kong with a minimum pressure of 3kPa and a

permissible maximum deflection of 1/180th of the length

of the member under consideration. Where necessary use

mild steel cores, anchors, brackets, etc. as stiffeners.Calculations are required to be submitted for approval.

Cores, anchors and brackets etc. shall be finished to


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Clause 17.33(p).

(existing) Clause

17.33

(e) Provide ....................................... lug

spaces............................... fixing bolts.

replace with (e) Provide ........................................ lugs spaced

............................... fixing bolts.

deleted Clause17.33

(g) to be deleted

(existing) Clause

17.33

(l)(ii)(a) diecast zinc alloy toBS 1004 suitably

coloured to match the anodised window or door

metal.

replace with (a) diecast zinc alloy to BSEN 1774 suitably coloured to

match the anodised window or door metal.

(existing) Clause

17.41

Roller shutters and ........................................ with the following

:-

Roller

shutters anddoors

(a) Steel roller shutters ...................................... shutter

against wear.

replace with (a) Roller shutters and doors shall be supplied and fixed in

accordance with the following :-

Steel roller shutters shall consist of horizontal hot dipped

galvanised slats which interlock through their entire length

to form a continuous hinge. The shutters shall be designed

to withstand a wind load calculated in accordance with the

Code of Practice on Wind Effects, Hong Kong with aminimum pressure of 3 kPa on the entire surface area of the

shutter or otherwise specified.

Roller

shutters and

doors

(existing) Clause

17.41

(d) Electrically operated shutters

.......................................... by the Architectural

Services Department.

replace with (d) Electrically operated shutters shall comply with the

Code of Practice for Installation of Electrically Operated

Sliding Gates, Sliding Glass Doors and Rolling Shutterspublished by the Electrical and Mechanical Services

Department. The shutters shall be installed complete with

electric motors, the associated overload protection, drive

mechanism, limit switches, emergency stop, control buttons and

other control devices required by the shutter manufacturer. The

electrical installation of the shutter shall comply with BS7671:

Regulations for Electrical Installations and the General

Specification for Electrical Installations in Government

Buildings, Hong Kong.


(n) An interlock switch .......................................... movingpart of the roller shutters.


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replace with (n) An interlock switch shall be provided to prevent the

locked roller shutters from operating electrically and

shall be fitted on a stationary part (such as the guide

rails) but not on the moving part of the roller shutters.

(existing) Clause

17.42

Fire resisting roller shutters shall satisfy the requirements of

BS 476:Part 8 for the specified period of resistance required.

The shutters shall be self-closing activated by fusible links or

electronic heat or smoke detectors. Test certificates will be

required.

Fire resisting

roller shutters

replace with Fire resisting roller shutters shall satisfy the requirements of

BS 476: Parts 20-23 for the specified period of resistance

required. The shutters shall be self-closing activated by fusible

links or electronic heat or smoke detector s. Test certificates

will be required.

Fire resisting

roller

shutters

(existing) Clause

17.43

The design of the roller ............................................... defective

materials, workmanship or design.

Design and

manufacturer

of rollershutters

replace with The design of the roller shutters, including boxes, hoods, guides

and all other parts shall be the responsibility of the Contractor.

Design and

manufacturer

of roller

shutters

SECTION 18

FINISHES (INCLUDING CARPETING AND RAISED FLOORING)


Lime to be as Clause 6.18. Lime

replace with Lime to be as Clause 9.18. Lime

(existing) Clause

18.05

Lime putty to be as Clause 6.19. Lime patty

replace with Lime putty to be as Clause 9.19. Lime patty

(existing) Clause

18.06

Admixtures and additives to be as Clause 6.19. Admixtures

and additives

replace with Admixtures and additives to be as Clause 6.36. Admixtures

and additives

(existing) Clause

18.08

Mix mortar or plaster as Clauses 6.21 to 6.23. Mixing

mortar of

plaster

replace with Mix mortar or plaster as Clauses 9.21 to 9.23. Mixing

mortar of

plaster

(existing) Clause

18.09

Provide sample panels of about 1 sq m2

for -------

replace with Provide sample panels of approximately 2 sq m2 for -------

(existing) Clause Apply spatterdash to concrete vertical surfaces and soffits Spatterdash


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18.15 immediately after striking formwork. Mix and apply as follows:

-

(i) Mix to consist of cement and coarse sand or granite fines in

the proportion of 1: 2.

(ii) Throw onto a thickness not exceeding 6 mm with a hand

scoop or a trowel and wet one hour after application.

(iii) Allow to cure and harden before applying undercoat.

replace with Clean all laitance, dust, oil or any other such substances from

the concrete surface.

Spatterdash to consist of (1:2) cement : coarse sand or granite

fines with an approved bonding agent such as a styrene-

butadiene rubber (SBR) latex, an ethyl vinyl acetate (EVA)

emulsion or an acrylic emulsion.

Apply spatterdash to concrete vertical surfaces and soffits

immediately after striking formwork.

The mixture shall be applied by dashing it on the wall to give a

complete coverage with a rough texture between 2 to 3 mm

thickness. The surface shall be maintained moist for 24 hours.

(iv) Allow to cure and harden for at least two days before

applying rendering / bedding screed.

Spatterdash

(existing) Clause

18.21

---- layer of damp sand. Keep covered for 7 days. Curing of

floor finishes,

etc.

replace with ---- layer of damp sand. Unless otherwise agreed by the SO,

keep covered for 7 days.

Curing of

floor finishes,

etc.

(existing) Clause

18.22

Movement joints are to be constructed at approximately 3m

centres in each direction equally spaced, in accordance with

Clauses 4.55 and 4.56, or as directed by the SO to accord with

dimensioned requirements.

Sealing

movement

joints

replace with Movement joints are to be constructed at a maximum 4m

centres in each direction equally spaced, in accordance with

Clauses 6.61 and 6.62, or as directed by the SO to accord with

dimensioned requirements.

Movement

joints

(existing) Clause

18.37

Fire cement to be as specified for firebrick mortar in Clause

6.21.

Fire cement

replace with Fire cement to be as specified for firebrick mortar in Clause

9.21.

Fire cement

(existing) Clause

18.46

Apply external rendering consisting of cement, lime and sand in

two coats as follows: -

External

render


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(i) First coat 10mm (minimum) thick - mix 1:2:6.

(ii) Finishing coat 10mm (maximum) thick - mix 1:3:6, with

textured finish.

Total thickness of external render is not to exceed 20mm.

replace with Clause

18.46

Apply external rendering to spatterdashed surfaces consisting of

cement and sand in two coats as follows:-

(i) Undercoat 10mm (minimum) thick --- mix 1:3

(ii) Finishing coat 10mm (maximum) thick --- mix 1:3, with

textured finish. Total thickness of spatterdash & external

rendering shall not exceed 20mm.

Undercoat must be thoroughly dry before application of the

finishing coat.

Pulverised Fly Ash (PFA) shall not be used for the external

rendering.

External

render

Add Clause

18.47

Pulverised Fly Ash (PFA) shall not be used for the internal

plastering.

(existing) Clause

18.103

(i) (d) Lay tiles and tamp firmly into bed with -----

replace with (i) (d) Lay tiles mixed from six boxes and tamp firmly into bed

with -----

(existing) Clause

18.103

(ii) (d) Lay tiles and tamp firmly into bed with -----

replace with (ii) (d) Lay tiles mixed from six boxes and tamp firmly into bed

with -----

(existing) Clause

18.107

(i) (a) Soak tiles in clean water for 30 minutes ----

replace with (i) (a) Soak tiles, mixed from six boxes, in clean water for 30

minutes ----


(ii) (a) If approved, fix wall tiles using a bed of adhesive in ----

replace with (ii) (a) If approved, fix wall tiles, mixed from six boxes, using a

bed of adhesive in ----

(existing) Clause

18.108

Fixing of external facing tiles to be as Clause 18.107 except

width of joints to be as specified.

Fixing

external

facing tiles

replace with Fix external wall tiles to spatterdashed surfaces as follows:-

(i) Thick bed method:-

(a) Apply wall screed of (1:3) cement : sand to a maximum

thickness of 10 mm. Allow the wall screed to dry off

thoroughly.

Fixing

external

facing tiles


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(b) Soak tiles in clean water for 30 minutes. Stack to drain and

fix as soon as the surface water has drained off.

(c) Apply a mortar slurry of (1:3) cement : sand with

water/cement ratio of 0.5 by weight to thickness of 10 mm

on the wall screed.

(d) The bedding surface of the tile shall be pre-filled with the

mortar slurry before fixing to the wall screed.

(e) The tile must be affixed by trowel knock procedures. Knock

the centre of tile using the handle of a trowel first and

followed by knocking all the edges of a tile till the mortar

slurry flows out from the tile edges.

(f) Joints to be minimum 2 mm wide, and maximum 3.5mm

wide.

(g) Make any adjustment to tiles within 10 minutes of fixing.

(h) Clean tiles and joints before the slurry hardens.

(i) Grout joints minimum 24 hours after fixing tiles. Clean off

surplus grout as work proceeds.

(j) Clean tiles at completion.

(ii) Thin bed method:-

(a) Apply wall screed of (1:3) cement : sand to a maximumthickness of 10 mm. Allow the wall screed to dry off

thoroughly.

(b) Fix wall tiles to the wall screed using an approved adhesive

in accordance with the manufacturer's recommendations.

(c) Grout joints using an approved grout.


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Carry out infra-red thermographic scanning by an approved

specialist and submit report within 4 months upon completion

of external tiling. Should the report indicate that any part of the

wall tiling has not been affixed properly, the Contractor shall

carry out approved remedial measures at his own expense and

carry out further infra-red thermographic scanning to the

satisfaction of the SO.

(existing) Clause

18.111

Fix stone wall slabs not less than 12mm from the structural

surfaces on Keenes cement or Plaster of Paris dabs. Space

slabs so that each slab is evenly supported by not less than five

dabs. Dowel for and fit each slab with copper cramps and S

hooks, formed from 5mm diameter copper wire. Fix slabs at

approximately 350mm centres or as directed and solidly bed

cramps to the structure and S hooks to backs of slabs.

Fixing stone

wall slab

replace with Generally fix stone wall slabs in accordance with Clause 16.09,

16.14 and 16.15 for heights greater than 1.2 metre above anystructural floor level. Fix stone wall slabs not less than 12mm

from the structural surfaces on Keenes cement or Plaster of

Paris dabs. Space slabs so that each slab is evenly supported by

not less than five dabs. Dowel for and fit each slab with copper

cramps and S hooks, formed from 5mm diameter copper wire.

Fix slabs at approximately 350mm centres or as directed and

solidly bed cramps to the structure and S hooks to backs of

slabs.

Fixing stone

wall slab

(existing) Clause18.126 All carpet shall be of approved type and colour and inaccordance with the following specification, of an approved

brand, laid and executed by a specialist on the Works Branch

List for Flexible Finishes.

Approvalbrands and

specialist

contractors

replace with All carpet shall be of approved type and colour and in

accordance with the following specification, of an approved

brand, laid on screed treated with an approved sealant to reduce

dust and pollution.

Approval

brands and

specialist

contractors

SECTION 19

PLUMBING(existing) Clause

19.01

All plumbing and above ground drainage work is to be in

compliance with the Water Authoritys requirements

Generally

replace with All plumbing is to be in compliance with the Water Authoritys

requirements and Waterworks Regulations

Generally

(existing) Clause

19.07

Plug to be as Clause 13.20 Plugs

replace with Plug to be as Clause 13.28 Plugs


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(existing) Clause

19.08(f

)

Pipe thread tape to be unsintered PTFE tape to BS4375 of an

approved proprietary brand.

replace with Pipe thread tape to be unsintered PTFE tape to BS7786 of an

approved proprietary brand.

(existing) Clause

19.11

Fix pipes and fittings securely with fixings and fastenings

appropriate to the locations and the material (refer to Tables

15.1 and 15.2). Avoid pipe runs above electrical switchgear.

Fixing pipes

replace with Fix pipes and fittings securely with fixings and fastenings

appropriate to the locations and the material (refer to Tables

19.1 and 19.2). Avoid pipe runs above electrical switchgear.

Fixing pipes

(existing) Clause

19.18

Where pipes pass through fire rated walls or floors to be as

Clause 19.13 but :-

Pipe through

fire rated

walls and

floors

replace with Where pipes pass through fire rated walls or floors to be as

Clause 19.17 but :-

Pipe through

fire rated

walls and

floors

(existing) Clause

19.23

Avoid contact between certain dissimilar metals as Clause

17.27.

In particular avoid the direct contact of copper with galvanized

iron or steel pipes.

Contact

between

dissimilar

metals

replace with Avoid contact between certain dissimilar metals in particular

avoid the direct contact of copper with galvanized iron or steel

pipes as Clause 17.26.

Contact

between

dissimilar

metals

(existing) Clause

19.40

The whole clause is deleted.

(existing) Clause

19.41

Screw threads to UPVC pipes are not allowed unless ordered

otherwise by the SO. Where screw connections are required,

screwed adapter bushes shall be used.Fix and joint plastic pipes

Documents

ASD Specification (Volumn 1 Corrigendum)