CSA Z240.2.1 Technical Requirements for Manufactured Homes ... of Major... · CSA Z240.2.1 Technical Requirements for Manufactured Homes – Implications of the More Significant Proposed

CSA Z240.2.1 Technical Requirements for Manufactured Homes – Implications of the More Significant Proposed Changes

Prepared for the CSA Technical Committee

21 March 2014

Z240.2.1 Technical Requirements for Manufactured Homes 21 March 2014

Implications of the More Significant Proposed Changes Page i

Contents

i

0. Introduction 1

1. Roof Deflections 2 1.1 Z240.2.1 and NBC Requirements 2 1.2 Implications of Referencing the NBC 2

2. Lintels 3 2.1 Z240.2.1 and NBC Requirements 3 2.2 Implications of Referencing the NBC 3

3. Resistance to Lateral Loads 4 3.1 Z240 MH and NBC Requirements 4 3.2 Implications of Referencing the NBC 4

4. Energy Efficiency 10

4A. Building Envelope – Climate Zones 10

4B. Building Envelope - Insulation 10 4B.1 Z240 MH and NBC Requirements 10 4B.2 Implications 12

4C. Building Envelope – Windows and Doors 13 4C.1 Z240 MH and NBC Requirements 13 4C.2 Implications 14

4D. Building Envelope – Tradeoffs 15 4D.1 NBC Requirements 15 4D.2 Implications 15

4E. Building Envelope – Airtightness 15 4E.1 Z240 MH and NBC Requirements 15 4E.2 Implications 16

4F. HVAC – Ducting and Piping 16 4F.1 Z240 MH and NBC Requirements 16 4F.2 Implications 17

4G. HVAC – Controls and Equipment 17 4G.1 Z240 MH and NBC Requirements 17 4G.2 Implications 18

4H. Service Water Heating – Piping and Equipment 18 4H.1 Z240 MH and NBC Requirements 18 4G.2 Implications 19

4J. Performance Path 20

References 20


Implications of More Significant Proposed Changes Page 1 of 20

0. Introduction

Proposed General Reference to the NBC

Many of the current requirements in Z240 MH Series are copies of requirements in the

National Building Code (NBC) or they reference NBC requirements. It is proposed that the

next edition of the standard reference the NBC as a general requirement and provide

explicit requirements and exceptions only where these are needed to address issues that

are specific to manufactured homes.

Implications – General

Where Z240 MH does not copy or reference NBC requirements, the resultant technical

changes may range from minimal to quite significant – sometimes making the requirement

less stringent and sometimes more stringent. This document provides information on the

proposed changes that could result in notably more stringent requirements.

Table 1 summarizes the impact of the proposed NBC reference depending on jurisdiction,

climate and seismic load.

Table 1 – Summary of Impact of General Reference to the NBC

Province, Territory

Z240 MH Recognized

Implications

Snow loads (1)

Lateral Loads (1)

Energy Efficiency (lintels) Wind Seismic

BC Yes Yes Yes Yes Yes

AB -- -- -- -- -- (4)

SK unofficially (2)

Yes -- -- Yes (5)

MB Yes, unofficially(3)

Yes -- -- Yes

ON Yes Yes -- -- Yes

QC depends on municipality

Yes -- Yes Yes

NB unofficially (2)

Yes -- -- Yes

NS Yes Yes -- -- -- (6)

PE depends on municipality

-- Yes

NL depends on municipality

Yes Yes -- Yes

YK Yes Yes -- Yes Yes

NT depends on municipality

Yes Yes -- Yes

NU depends on municipality

Yes -- -- Yes

Notes on Table:

(1) Does not affect all locations

(2) Z240 MH homes are accepted even though the standard is not recognized in the applicable regulation.

(3) Z240 MH homes appear to be accepted beyond the regulated limit to “mobile homes”.

(4) Alberta has indicated its intent to adopt the NBC Part 9 energy efficiency requirements.

(5) Saskatchewan has plans to adopt the NBC Part 9 energy efficiency requirements.

(6) Nova Scotia’s energy efficiency requirements apply to all Part 9 buildings



1. Roof Deflections

1.1 Z240.2.1 and NBC Requirements

Limits and Test Criteria

Table 2 provides the deflection limits and test criteria for deflection limits and

sustained loads for roof beams, rafters, joist and trusses as specified in the current

Z240.2.1 and the NBC.

Table 2 – Z240.2.1 and NBC Roof-Ceiling Deflection Requirements

Roof-Ceiling Assembly Deflection limit Test criteria

Z240.2.1 NBC Z240.2.1 NBC*

Beams, rafters or joists* 9.4.3.1. 9.4.3.1.

gypsum board or plaster L/360 L/360

- live load

- good engineering

practice

- dead loads need not be considered

- otherwise, design per Part 4

other than gypsum board or

plaster

span ≥ 4.3 m L//240 L/240

span < 4.3 m L/180 L/240

no ceiling

span ≥ 4.3 m L/240 L/180

span < 4.3 m L/180 L/180

Trusses – when tested 9.23.14.11. 9.23.14.11.

(sustained) 2-2/3 x design roof

snow load for 24 h

total ceiling load (dead load + live load) of

0.35 kPa +

2-2/3 x specified live roof load for 24 h

gypsum board or plaster L/360 L/360

1-1/3 x design roof

snow load after 1 h

ceiling load +

1-1/3 * specified roof snow load for 1 h

not gypsum board or plaster

span ≥ 4.3 m L//240 L//240

span < 4.3 m L/180 L/180

Notes to Table:

* Z240.2.1. does not mention roof joists.

1.2 Implications of Referencing the NBC

Beams and Rafters

no change for beams or rafters where the ceiling is gypsum board

Trusses

where trusses are tested, ceiling load must be added for sustained loading

and deflection to recognize increasing loads from insulation

no change where compliance is demonstrated by calculation

Note

In the 2015-2020 code development cycle, the Standing Committee on Housing and

Small buildings will be reviewing the differences between the requirements for

trusses compared to those for beams, rafters and joists. There is also a proposed

change to delete the testing option.



2. Lintels

2.1 Z240.2.1 and NBC Requirements

Table 3 provides:

the current Z240.2.1 Table 4 Wood Lintel Spans, and

an excerpt from NBC Table A-15 Maximum Spans for Spruce-Pine-Fir Lintels, No.

1 or No. 2 Grade, Non-structural Sheathing showing the spans for lintels

supporting roof and ceiling only with a tributary width of 4.9 m maximum.

Comparable spans are highlighted.

Table 3 – Z240.2.1 and NBC Lintel Requirements

Z240.2.1 Table 4 Excerpt from NBC Table A-15

Depth of lintel, mm Maximum allowable span, m

Lintel size

Maximum Span, m

38 mm × 64 mm

studs*

Studs exceeding

38 mm × 64 mm†

Exterior Walls Int’r walls

Specified Snow Load, kPa

1.0 1.5 2.0 2.5 3.0

140 89 1.12 2-38x89 1.27 1.11 1.01 0.93 0.87 0.93

184 140 1.68 2-38x140 1.93 1.66 1.48 1.35 1.25 1.35

235 184 2.24 2-38x184 2.35 2.02 1.80 1.64 1.52 1.64

— 235 2.79 2-38x235 2.88 2.47 2.20 2.01 1.84 2.01

— 286 3.35 2-38x286 3.34 2.87 2.56 2.33 2.09 2.33

*Lintels consist of one 38 mm thick piece of lumber and one 19 mm thick piece of lumber on edge. †Lintels consist of two pieces of 38 mm thick lumber on edge, separated by filler pieces.

Compared to the NBC spans, the Z240.2.1 spans:

do not address snow loads exceeding 1.5 kPa nor 1.0 kPa for longer spans

NBC span table values have changed over time to recognize changes in lumber

properties.


Lintel dimensions would increase where snow loads exceed 1.5 kPa and

where they exceed 1.0 kPa for longer spans.

The lintel dimensions would recognize:

changes in lumber properties

snow loads in 286 to 416 additional locations (depending on building width) that

exceed 1.5 kPa.

While the NBC does not explicitly recognize 38 mm x 64 mm load bearing studs,

these could still be used based on equivalence, or a change request could be

submitted to have these added to the Code.



3. Resistance to Lateral Loads

While the NBC lateral load resistance requirements appear to be complicated, many

sentences, clauses and table entries do not apply to single storey homes with normal

weight roofing.

3.1 Z240 MH and NBC Requirements

Application

The application of the current Z240 MH and NBC requirements is summarized in

Table 4.


Overview

For most locations identified in NBC Appendix C, traditional construction

practice is unaffected by the lateral load requirements.

As shown in Table 3, homes installed on Resolution Island, NU and in La Malbaie,

Baie Saint Paul and La Pocatiere, QC must be deigned according to Part 4.

The following describes the implications for manufactured homes that may be

designed and constructed under Part 9 but where additional lateral resistance is

required. For many designs, it is likely that the only changes will be:

the construction of braced wall panels in one interior partition

additional fastening of

- rim joists/beams to the sill plate

- braced wall panels to framing above and below

- roof framing to wall framing (a few locations for wind only)

- sheathing and interior finishes that provide required lateral resistance.

Where the home is constructed on a steel frame, the fastening of the floor

assembly to the frame will need further review and is proposed to be addressed

in the context of updates to Z240.10.1 regarding seismic loads.

Important Terminology

Term Definition Shown in Plan

Figures as

Braced wall

band

an imaginary continuous straight band extending

vertically and horizontally through the building or

part of the building, within which braced wall panels

are constructed

Braced wall

panel

a portion of a wood-frame wall where bracing,

sheathing, cladding or interior finish is designed and

installed to provide the required resistance to lateral

loads due to wind or earthquake



Table 4 – Z240 MH Requirements and Application of NBC Requirements

Wind), kPa

1-in-50 hourly wind pressure (HWP

Seismic

seismic spectral response acceleration (Sa(0.2))

Z240 MH all locations 0.70* no requirements

NBC

Traditional

construction

all locations not identified below all locations not identified below

Additional

lateral

resistance

required

0.80 ≤ HWP ≤1.2 kPa 0.70 < Sa(0.2) < 1.2

Northwest Territories

Holman /Ulukhaqtuuq 0.86

Alberta

Cowley 1.01

Pincher Creek 0.96

Newfoundland and Labrador

Cape Race 1.05

St Anthony, NF 0.87

Bonavista 0.84

British Columbia

Langford 1.2

Sidney 1.20

Tofino 1.20

Ucluelet 1.20

Victoria (Gonzales Hts) 1.20

Victoria (Mt Tolmie) 1.20

Victoria 1.20

Bamfield 1.10

Crofton 1.10

Duncan 1.10

Ladysmith 1.10

Sooke 1.10

Cloverdale 1.10

Ladner 1.10

Langley 1.10

White Rock 1.1

Nanaimo 1.00

Port Renfrew 1.00

Richmond 1.00

Surrey (88 Ave & 156 St.) 1.00

Youbou 1.00

Abbotsford 0.99

Jordan River 0.99

New Westminster 0.99

Haney 0.97

Vancouver 0.95

(Granville & 41 Ave)

Vancouver 0.94

(City Hall)

Mission City 0.93

Burnaby 0.93

(Simon Fraser Univ.)

North Vancouver 0.88

West Vancouver 0.88

Sechelt 0.87

Tahsis 0.87

Parksville 0.86

Qualicum Beach 0.82

Gold River 0.80

Chilliwack 0.76

Port Alberni 0.76

Alberni 0.75

Squamish 0.72

Quebec

Riviere du Loup 1.00

St-Georges-de-Cacouna 0.80

Montmagny 0.73

Yukon

Destruction Bay 0.73

Haines-Junction 0.72

Design to

Part 4

HWP >1.2 kPa

Resolution Island, NU 1.23

Sa(0.2) ≥ 1.2

La-Malbaie, QC 2.30

Baie Saint Paul, QC 2.10

La Pocatiere, QC 2.00

Note to Table:

* The proposed change to Z240.2.1 clause 6.2.1.1 (5.2.3) would require design to 0.70 kPa or the HWP at the installation site

whichever is greater.

NBC 9.23.13.1. to 9.23.13.3.

No technical implications beyond the application described above.

NBC 9.23.13.4. Braced Wall Bands

Requirements Relevant to Manufactured Homes

Braced wall bands are limited to max. 1.2 m wide

Exterior walls must be located within the braced wall bands

Max. spacing between centre-lines of braced wall bands are as shown in Table 5.



Table 5. – Max. Spacing of Braced Wall Bands

Seismic Wind

0.70 < Sa(0.2) < 1.0 1.0 ≤ Sa(0.2) < 1.2 0.80 ≤ HWP ≤1.2 kPa

Maximum distance between centre

lines of braced wall bands, m (ft) 10.6 (34.78’) 7.6 (24.94’) 7.6 (24.94’)

Implications

where there are jogs in an

exterior wall

the entire wall must

be located within the

1.2 m–wide braced

wall band (Fig. 1a),

OR

the lines of both walls

must be considered to

be on braced wall

bands and the

requirements for

braced wall panels

apply to both bands

(Fig. 1b)

where length (or less

likely, width) of a module

is greater than the limits

in Table 5 plus 1.2 m,

intermediate cross-walls

must be constructed with

braced wall panels

(Fig. 1c).

NBC9.23.13.5. Braced Wall Panels (Spacing and Dimensions)


1. Braced wall panels must be within braced wall bands.

2. Except as described in point 4, maximum spacing and minimum dimensions of

braced wall panels must be as shown in Table 6.

3. The maximum distance between braced wall panels may be increased to 7.3 m

provided that the length of all the braced wall panels within the braced wall band

is not less than 1.2 m. [NBC 9.23.13.7. Additional System Considerations]

4. Exception for Sunrooms

The perimeter of a single space need not comply with points 1. to 3. above

provided the roof of the space is framed max. 400 mm o.c. and:

a) projects not more than

- 3.5 m from the face of the framing in the nearest parallel braced wall

band, and

- half the perpendicular plan dimension,

b) is either

- integral with the roof of the rest of the building, or

- fastened to the wall framing.

Figure 1 – Braced Wall Bands

Fig. 1a Fig. 1b Fig. 1c



Table 6 – Spacing and Dimensions of Braced Wall Panels

Seismic Wind

0.70 < Sa(0.2) < 1.0 1.0 ≤ Sa(0.2) < 1.2 0.80 ≤ HWP ≤1.2 kPa

Maximum distance between edges of braced

wall panels, m (ft) 6.4 (21) 6.4 (21) 6.4 (21)

Maximum distance from end of a braced wall

to the edge of the closest braced wall panel,

m (ft)

2.4 (7.87) 2.4 (7.87) 2.4 (7.87)

Minimum length of individual braced wall panels

panel located at the end of a braced wall band where the braced wall panel connects to an intersecting braced wall panel, mm (in)

600 (23.62)

panel not located at the end of a braced wall band or braced wall panel located at the end of a braced wall band where the braced wall panel does not connect to an intersecting braced wall panel, mm (in)

750 (27.76)

Minimum total length of all braced wall panels in a braced wall band

25% of braced wall band

Implications

See Figure 2 as an example.

Figure 2 – Spacing Dimensions for Braced Wall Panels

27

’-0

”

max. 1.2 m

max. 7.6 m max. 7.6 m

ma

x. 7

.6 m

m

ax. 7

.6 m

max. 6.4 m

max. 1.2 m

max. 6.4 m

max. 2.4 m

min 600 mm

min. 750 mm

min 600 mm



NBC 9.23.13.6. Materials in Braced Wall Panels


In general, normal structural sheathing and interior gypsum board with

minimum thicknesses shown in Table 7 must be installed and with options if

wood-based interior finishes are used

For modules more than 15 m (49.2’) long, the braced wall panels in one

intermediate braced wall must be constructed with OSB or plywood on

both sides.

Table 7 – Braced Wall Panel Materials and Thicknesses

Panel Type Cladding, Sheathing or Interior Finish Minimum Thickness, mm

With supports 400 mm o.c.

With supports 600 mm o.c.

Gypsum board interior finish 12.7 15.9

Sheathing complying with CAN/CSA-O325 W16 W24

OSB O-1 and O2 grades and waferboard R-1 grade 9.5 12.5

Plywood 9.5 12.5

Diagonal lumber 17 17

Other NBC Requirements and Implications

Other requirements that apply and their implications are summarized in Table 8.

Table 8 – Other Requirements to Address Wind Load and Implications

Code Ref Subject, Application Implications

9.23. Wood-Frame Construction

9.23.3.4. Nailing of Framing

Sentence (1) and

Table 9.23.3.4.

wind and seismic closer centres - 150 mm o.c.

vs. 2 per joist or blocking for rim joist, trimmer joist or

blocking supporting braced wall panels to sill plate or top

wall plate

vs. 400 mm o.c. – exterior walls – bottom plate of braced

wall panels to floor joists, rim joists or blocking

vs. 600 mm o.c. to framing below – interior walls – to framing

above and below

Sentences (3)(4) wind only tying roof framing to wall framing

min. 50 mm x 0.91 mm (2” x 21 gage) galvanized strips

9.23.3.5. Fastening for Sheathing

Sentence (2) and

Table 9.23.3.5.-B

wind and seismic increased fastener lengths

wind only roof sheathing – 50 mm o.c. within 1 m of roof edges

9.23.6.1. Anchorage

Sentence (3) -- no implications for 1-storey buildings

9.23.9.8. Support of Walls (that provide required lateral resistance)

Sentence (6) wind and seismic continuous support required

9.23.16.1. Required Roof Sheathing no implications

continuous lumber or panel-type sheathing required Sentence (1) wind and seismic

9.23.16.5. Lumber roof sheathing no implications

lumber sheathing must be diagonal Sentence (2) wind and seismic

Table continued next page …



Table 8 (Continued)

Code Ref Subject, Application Implications

9.29.5. Gypsum Board Finish

9.29.5.8. Spacing of Nails Closer centres where gypsum board provides required lateral

resistance

- max. 200 mm o.c. Sentence (4) wind and seismic

9.29.5.9. Spacing of Screws Closer centres where gypsum board provides required lateral

resistance

max. 300 mm o.c. Sentence (4) wind and seismic

9.29.6. Plywood Finish

9.29.6.3. Nails and Staples increased fastener lengths

fastening in accordance with requirements for sheathing –

Sentence 9.23.3.5.(2) Sentence (2) wind and seismic

9.29.9. Particleboard, OSB or Waferboard Finish *

9.29.9.3. Nails increased fastener lengths

fastening in accordance with requirements for sheathing –

Sentence 9.23.3.5.(2) Sentence (2) wind and seismic

Note to Table 7:

* Particle board is not permitted to be used to provide required lateral resistance

An alternative recognized by Part 9 is design according to the Canadian Wood Council’s

Engineering Guide for Wood Frame Construction.



4. Energy Efficiency

4A. Building Envelope – Climate Zones

The NBC building envelope energy efficiency requirements vary depending on climate

zone. See Figure 3.

Figure 3 – Climate Zones and Heating Degree Days

4B. Building Envelope - Insulation

4B.1 Z240 MH and NBC Requirements

General Thermal Insulation Requirements

For the six climate zones, Table 9 shows

the Z240 MH insulation RSI values and (R-values) in bold black

NBC RSI values and (equivalent insulation R-values) in blue,

with optional reduced values for houses with an HRV in green italic.

Zone 8

Zone 7B

Zone 7A

Zone 7A

Zone 6

Zone 8

Zone 7B

Zone 6

Zone 5

Zone 5

Zone 4

Zone 6

Zone 5



Table 9 –NBC and Z240 MH Thermal Resistance Requirements (1)

Climate Zone and

Maximum Number of

Heating Degree Days,

˚C

Floors Walls Attics Cathedral Ceilings,

Flat Roofs

Effective

RSIe

Insulation,

RSI (R) (2)

Effective

RSIe(3)

Insulation,

RSI (R) (4)

Effective

RSIe

Insulation,

RSI (R) (5)

Effective

RSIe

Insulation,

RSI (R) (6)

Zone 4 < 3000

4.67 5.47 (31)

2.78 3.45 (19) 6.91 7.1 (40) 4.67 5.47 (31)

Zone 5 3000 to 3999

4.67 5.47 (31)

3.08

2.97

4.23 (24)

3.88 (22)

8.67

6.91

8.8 (50)

7.1 (40)

4.67 5.47 (31)

Zone 6 4000 to 4999

4.67 5.47 (31)

3.08

2.97

4.23 (24)

3.88 (22)

8.67 8.8 (50) 4.67 5.47 (31)

Zone 7A 5000 to 5999

Less than 6000

5.02 6.0 (35)

4.7 (27)

3.08

2.97

4.23 (24)

3.88 (22)

3.0 (17)

10.43

8.67

10.9 (60)

8.8 (50)

5.7 (32)

5.02 6.0 (35)

5.7 (32)

Zone 7B 6000 to 6999

5.02 6.0 (35) 3.85

3.08

4.83 (24+3.4)

4.23 (24)

10.43 10.9 (60) 5.02 6.0 (35)

Zone 8 ≥ 7000

6000 to less than 8000

5.02 6.0 (35)

4.7 (27)

3.85

3.08

4.83 (24+3.4)

4.23 (24)

3.87 (22)

10.43 10.9 (60)

6.7 (38)

5.02 6.0 (35)

6.7 (38)

8000 and more 5.02 6.0 (35)

4.7 (27)

3.85

3.08

4.83 (24+3.4)

4.23 (24)

3.87 (22)

10.43 10.9 (60)

7.0 (R40)

5.02 6.0 (35)

7.0 (R40)

Notes to Table:

(1) Z240 MH values in bold black; NBC values without HRV in blue; NBC values with HRV in green where these differ from values without HRV

(2) Insulation values for floors assume lumber framing at 400 mm (16”) o.c. Using wood-I joists would permit the use of RSI 494 (R28) and RSI 547 (R31) in Zones 4-6 and 7A-8 respectively.

(3) Air films, hollow-backed vinyl siding, 9.5 mm (3/8”) OSB exterior sheathing, 12.7 mm (1/2”) interior gypsum board contribute RSI 0.43 (0.03+ 0.11+0.093+0.08+0.12). 25 mm Type 1 expanded polystyrene insulation contributes an additional RSI 0.65 (R 3.4) for a total of RSI 1.08

(4) Insulation values for walls assume 38 mm x 140 mm (2” x 6”) framing at 400 mm (16”) o.c. Insulation values illustrate examples of compliant assemblies most likely to be used for manufactured homes.

(5) Insulation values for attics assume framing at 600 mm (24”) o.c.

(6) Insulation values for cathedral ceilings and flat roofs assume framing at at 400 mm (16”) o.c. Using wood-I joists would permit the use of RSI 494 (R28) and RSI 547 (R31) in Zones 4-6 and 7A-8 respectively.

Additional Thermal Insulation Requirements

Structural Penetrations

NBC requirements address major structural penetrations through the insulation.

These will typically not apply to manufactured homes.

Permitted Reductions for Services Installed within the Building Envelope

The effective thermal resistance of walls must be maintained where mechanical,

plumbing or electrical components (pipes, ducts, conduits, cabinets, chases, panels,

recessed heaters, etc.) are placed within the wall assembly. Except for ducts, where

these are placed within a floor assembly, the floor insulation may be reduced to

provide not less than RSIe 2.78. (Re 15.8). Where a duct is installed below the floor

framing, further reductions are permitted provided additional insulation is provided

on the sides of the duct.



Rim Joists

Rim joists must be insulated to the same level as the walls above.

Attic Insulation at the Eaves

The NBC

specifies a minimum RSI 3.52 (R-20) over exterior walls compared to the

Z240.2.1 minimum of RSI 2.1 (R12), and

limits the zone of reduced insulation to 1200 mm measured from the exterior of

the wall.

4B.2 Implications

General

Table 10 summarizes the implications of the NBC insulation requirements

Table 10 – Summary of Implications of

NBC Thermal Resistance Requirements

Climate Zone

Floors Walls Attics Cathedral Ceilings,

Flat Roofs (1)

Zone 4 Where installed

in joist space,

requires min.

10” floor joists

Insulation >R-20 in

2” x 6” stud spaces

or advanced

framing (2)

Significant increases.

See below re.

Attic Insulation at Eaves

4D. Building Envelope Trade-Offs

No implications Zone 5

Zone 6

Zone 7A Where installed

in joist space,

requires min.

12” floor joists

Requires exterior

insulation, HRV, or

insulation >R-20 in

2” x 6” stud spaces

plus advanced

framing (2)

Increase by R-3

Zone 7B

No implications Zone 8

Notes to Table: (1) The NBC Standing Committee on Housing and Small Buildings will be reviewing the NBC limits for cathedral

ceilings and flat roofs in the 2015-2020 code development cycle. (2) Some work has been done to show that R-20 batts and advanced framing can provide RSI 3.5 with

reduction in framing cost. Further work is needed to demonstrate the benefits of advanced framing where higher RSI values are required.

Attic Insulation at the Eaves

The minimum RSI 3.52 (R-20) over the exterior walls can be achieved with a 2 x 6

upper chord and a compressed R22 batt.

The 1200 mm horizontal limit for reduced insulation precludes 3/12 roof slopes

except in the mildest climate zone unless the trusses have raised heels.



4C. Building Envelope – Windows and Doors

4C.1 Z240 MH and NBC Requirements

General

Z240 MH specifies no thermal performance criteria for windows or skylights.

Z240 MH specifies min. RSI 0.7 for doors. This is equivalent to maximum overall

thermal transmittance (U) of 1.43. This limit, however, applies only where the 2.5%

January design temperature is lower than -15˚C while the NBC criteria are based on

heating degree days. The January design temperature is an appropriate metric for

systems design but not for energy efficiency. There are locations listed in NBC

Appendix C that are in climate Zones 4 to 7A where the January 2.5% design

temperature is -15˚C or warmer.

Table 11 identifies the NBC performance criteria for windows doors and skylights.

Table 11 –NBC Requirements for Windows, Doors and Skylight

Climate Zone Windows and Doors Skylights

Max. U Min. Energy Rating Max. U

Zone 4 1.8 21 2.9

Zone 5 1.8 21 2.9

Zone 6 1.6 25 2.7

Zone 7A 1.6 25 2.7

Zone 7B 1.4 29 2.4

Zone 8 1.4 29 2.4

Exceptions

One exterior door is permitted to have a maximum U 2.6.

Note re. British Columbia

The British Columbia Energy Efficiency Act specifies criteria for windows, skylights,

sliding glass doors and hinged doors. These apply to all buildings. The criteria that

would apply to manufactured homes are provided in Table 12. Exceptions are

permitted for windows, skylights and sliding glass doors provided the average

performance of all units meets the minimum performance level.

Table 12 –BC Energy Efficiency Act Criteria

Component Max. U-value

Windows and Sliding Glass Doors

frame other than wood or metal

wood frame

metal frame

2.00 2.00 2.57

Skylights 3.10

Hinged Doors 2.00



4C.2 Implications

Windows

NBC

The criteria for site-built windows provide some indication of the types of

windows that may comply with the performance criteria. These are provided

in Table 13.

Table 13 –NBC Criteria for Site-Built Windows

Climate Zone

Option

Frame Glazing Low-e coating Spacer

non-metallic

thermally broken metallic

double triple argon-filled

none panes with ≤ 0.10

panes with ≤ 0.20

size, mm

non-metallic

4 and 5 1 X -- -- X -- X -- -- 12.7 --

2 X -- X -- X -- ≥ 1 -- -- X

3 -- X -- X -- -- -- 2 12.7 --

6 and 7A

1 X -- -- X X -- -- ≥ 1 ≥

12.7 --

2 X -- -- X -- -- -- 2 12.7 --

3 -- X -- X X -- -- ≥ 2 ≥

12.7 --

7B and 8

1 X -- -- X -- -- ≥ 2 -- ≥

12.7 --

2 X -- -- X X -- -- ≥ 2 ≥

12.7 --

British Columbia

For homes installed in BC, compliance with the Energy Efficiency Act is less onerous

than compliance with the NBC. (The BC Building Code requirements are the same as

the NBC.)

Doors

NBC

Except where the Z240 MH requirement does not apply, the NBC criteria are

less stringent than Z240 MH in climate Zones 4 to 7A. Considering the

exception in the NBC, if a home has only one hinged door, all the NBC requirements

are less stringent.

British Columbia

The BC EE Act is less stringent than the NBC. (The BC Building Code requirements

are the same as the NBC.)



4D. Building Envelope – Tradeoffs

4D.1 NBC Requirements

With some limitations such as maximum reduction in RSI, the NBC allows trade-offs

as shown in Table 14.

Table 14 – Permitted Building Envelope Trade-Offs

Application Reduced Performance Permitted

Balanced by Increased Performance

All homes one or more opaque areas of the building envelope

one or more opaque areas of the building envelope

All homes one or more windows one or more windows

Homes where:

total window and door area (excluding skylights) ≤ 15% of the gross wall area

subfloor to ceiling ≤ 2.34 m (7’-8”)

subfloor to bottom truss chord or ceiling joist ≤ 2.39 m (7’-10”)

one or more floor areas or ceiling areas under sloped roofs

provided by difference between 17% window, skylight and door area and actual window, skylight and door area

Trading Floor and Attic Insulation for Window and Door Areas

The NBC trade-off permitting reduced floor and/or attic insulation where windows

and door area is limited recognizes the dimensional challenges faced by

manufactured homes in some regions of the country.

4D.2 Implications

Reduced Attic Insulation where Window Area is Limited

Calculations indicate that attic insulation can be reduced to less than R50 in all

instances where there is limited window area and that the required insulation

can be installed in 14’-wide homes with 4/12 roof slope. To maintain this low level of

attic insulation in the two coldest climate zones, either additional exterior

wall insulation or an HRV must be installed.

4E. Building Envelope – Airtightness

4E.1 Z240 MH and NBC Requirements

General

Z240.2.1 currently references the NBC building envelope requirements for air

barriers. The proposed general reference to the NBC would include the Section 9.36.

Energy Efficiency requirements as well. These provide the options of complying with:

a set of prescriptive construction requirements

a maximum leakage rate of 0.02 L/(s*m2) when tested according to

CAN/ULC‐S742, “Air Barrier Assemblies – Specification” at 75 Pa



OR

a maximum leakage rate of 0.02 L/(s*m2) when tested according to ASTM E

2357, “Determining Air Leakage of Air Barrier Assemblies” where the building will

not be subjected to 1/50 sustained wind loads exceeding 0.65 kPa. (This

standard could be used for all but 27 locations listed in NBC Appendix C.)

Specific

The NBC energy efficiency requirements for air barriers specify:

air barrier material compliance with CAN/ULC‐S741, “Air Barrier Materials –

Specification”

sealant material compliance with one of a number of standards

specific constructions for various penetrations, joints and junctions.

4E.2 Implications

Compliance with Test

Standard factory-construction practices should be such that manufactured homes

should comply with the performance limit of 0.02 L/(s*m2) when tested at 75 Pa.

Compliance with prescriptive Requirements

The prescriptive construction requirements essentially describe accepted good

practice. Standard factory-construction practices should be such that manufactured

homes should comply.

4F. HVAC – Ducting and Piping

4F.1 Z240 MH and NBC Requirements

Duct Sealing and Insulation

The application of the NBC duct sealing requirement is not as broad as in Z240 MH.

The NBC, however, does not permit the use of fabric‐backed tape with rubber

adhesives to provide the required airtightness.

Z240 MH requires exposed ducts to be insulated to a minimum of RSI 1.23 (R-7).

The NBC requires, in general, that ducts be insulated to the same level as walls. An

exception allows a minimum RSI 2.11 (R-12) under ducts installed under an

insulated floor provided additional insulation is installed on the sides so that there is

no increase in the total heat loss. An Appendix table provides a number of deemed-

to-comply solutions for various climate zones and duct dimensions.

Pipe Insulation

The NBC requires that piping installed outside the building envelope, except

high‐temperature refrigerant piping, be insulated to the same level as walls.

Z240 MH has no requirement.



Dampers

The NBC requires all duct openings to be equipped with a damper except:

where dampers are not permitted by other regulations

on air intakes in locations with fewer than 3500 heating degree days (climate

Zone 4 and some locations in climate Zone 5).

4F.2 Implications

Duct Sealing and Insulation

Sealing

Manufactured homes should comply with the NBC requirement provided fabric-

backed tape with rubber adhesive is not used.

Insulation

Depending on the proximity of ducting to the eaves, manufactured homes should be

able to meet the insulation requirement for ducts installed in attics.

For single-section homes where transportation height limits are stringent, the

insulation of ducts installed under the floor framing is more of a challenge. With

additional insulation on the sides of the duct, RSI 2.11 can be used in Zone 4, and in

Zones 5 to 7A provided an HRV is installed. Otherwise, additional thickness must

be provided or the insulation material must be more effective. The latter

should become a practical option with the expected approval of an NBC proposed

change to permit foam plastic insulation for ducts (some limitations apply).

Dampers

Except in climate Zone 4 and some locations in climate Zone 5, depending on current

practice there may be an additional cost for dampers.

4G. HVAC – Controls and Equipment

4G.1 Z240 MH and NBC Requirements

Controls

The NBC requirements specify various types of controls that must be installed and

required characteristics of those controls.

Equipment

The NBC specifies required performance levels for HVAC equipment. Equipment

efficiencies are the same or somewhat more stringent than the energy efficiency

ratings specified by the national Energy Efficiency Act. Table 15 provides a few

examples for heating equipment.



Table 15 – Selected Heating Equipment Efficiencies

Equipment Min. Performance

gas-fired warm air furnace AFUE ≥ 92%

gas fired unit heater Et ≥ 82%

oil-fired warm air furnace AFUE ≥ 85%

4G.2 Implications

Controls

Required controls are standard.

Equipment

Incremental costs as of December 2011 are provided in Table 16 for gas- and

oil-fired forced air furnaces. There is no incremental cost for electric heating.

Table 16 – Selected Incremental

Heating Equipment Costs (Ref. 3)

Factory Location

Fuel

Gas/Propane Oil

Vancouver $286 $1,144

Edmonton $291 $1,165

Winnipeg $280 $1,123

Toronto $260 $1,040

Montreal $260 $1,040

Halifax -- $ 998

4H. Service Water Heating – Piping and Equipment

4H.1 Z240 MH and NBC Requirements

Piping - Insulation

The NBC requires

the first 2 m of piping to and from the storage tank to be insulated with min.

12 mm thick pipe insulation

piping installed outside the building envelope to be insulated to the same level as

required for the walls.



Equipment

The NBC specifies required performance levels for service water heating equipment.

Equipment efficiencies are the same or somewhat more stringent than the energy

efficiency ratings specified by the national Energy Efficiency Act. Table 17 provides a

few examples.

Table 17 – Selected Service Water Heating

Equipment Efficiencies

Equipment Min. Performance

Storage-Type

electric SL ≤ 35 + 0.20V (top inlet) SL ≤ 40 + 0.20V (bottom inlet)

gas fired EF ≥ 0.67 – 0.0005V

oil-fired EF ≥ 0.59 – 0.0005V

Tankless

gas fired EF ≥ 0.80

oil-fired EF ≥ 0.59 – 0.0019V

4G.2 Implications

Piping

Incremental costs as of December 2011 for pipe insulation are provided in

Table 17.

Table 17 –Insulation Costs

Factory Location

Incremental Cost

Vancouver $55

Edmonton $56

Winnipeg $54

Toronto $50

Montreal $50

Halifax $48

Equipment

Incremental costs as of December 2011 are provided in Table 18 for

selected equipment.



Table 18 – Selected Incremental

Service Water Heating Equipment Costs

Factory Location

Energy

Gas/Propane Electricity, Oil

Vancouver $483 $175

Edmonton $492 $175

Winnipeg -- $175

Toronto $439 $175

Montreal -- $175

Halifax -- $175

4J. Performance Path

The NBC provides the option of demonstrating compliance through a performance

compliance path. Energy consumption is calculated for the proposed house and for a

reference house of the same dimensions and orientation designed according to the

prescriptive requirements for the same installation location. The proposed house

complies provided it uses no more energy than the reference house.

This option allows for considerable flexibility in the design of the house.

References

1. CAN/CSA-Z240-09 MH Series Manufactured Homes. Canadian Standards Association,

Toronto, 2009

2. National Building Code of Canada 2010, 2012 Revisions. National Research Council of

Canada. Ottawa, 2010.

3. Cost and Benefit Analysis of Proposed Changes for the Energy Efficiency in Housing

and Small Buildings in the National Building Code. Proskiw Engineering. December 13

2011.

4. Proposed Changes for the Energy Efficiency in Housing and Small Buildings in the

National Building Code – Building Envelope – Cost Estimate Analysis. Hanscomb

Consultants. Ottawa, September 26, 2011.

5. Proposed Changes for the Energy Efficiency in Housing and Small Buildings in the

National Building Code – HVAC and service Water Heating Systems – Cost Estimate

Analysis. Hanscomb Consultants. Ottawa, September 26, 2011.

Documents

CSA Z240.2.1 Technical Requirements for Manufactured Homes ... of Major... · CSA Z240.2.1 Technical Requirements for Manufactured Homes – Implications of the More Significant Proposed