1995 Building Code proposals call for upgraded ventilation standards

Publisher’s version / Version de l'éditeur:

Home Builder Magazine, May/June, p. 25, 52, 1990-05

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1995 Building Code proposals call for upgraded ventilation standards

Haysom, J. C.

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1 9 9 5 Building Code proposa ls c a ll for upgra de d ve nt ila t ion st a nda rds

N R C C - 3 4 9 8 8

H a y s o m , J . C .

M a y 1 9 9 0

A version of this document is published in / Une version de ce document se trouve dans:

Home Builder Magazine, May/June, pp. 25, 52, May, 1990

The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42

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'995 Bui/ding Code ProPOSII/S CIII/lor

Upgrtlded Ven,i/lI,ion"lIndllrds

.foImc. Haysom, senior technical advisor witb tbe

CodesSection, Institutefor Research in Construction,

NatlOlUll Research Council,

Ottawa.

•••

"The committee hopes

manufacturers will be

encouraged to begin

or accelerate

product development,

to comply

witb

F326."

•

Making changes to the National Building Code (NBC) is a careful process that often takes a long time.

The 1990 version of the Code Is not out yet, but work is already underway on changes for the 1995 version. One of those changes is expected to be the referencing, as mandatory, of a new CSA sundard on ventilation of houses - F326 "Residential Mechanical Ventilation Requirements."

F326 defines the requirements for mechanical venti-lation systems which provide ventiventi-lation air to the liv-ing spaces of sliv-ingle·family dwellliv-ings that come under Part 9 of the NBC and which are self-contained with

respect to heating, ventilating and air conditioning.

In February, theStandlng Committee on Housing and Small Buildings (the committee responsible for Part 9of the NBC) agreed there is much to recommend making compliance with F326 mandatory in the 1995 NBC, although there are reservations. The Sunding

Commit-tee hopes that this early announcement of its intention

will e1icir comments by those likely to be affected and will provide a focus and scheduie for a number of activities.

Among these is research on ventilation of houses, right now the most active area of housing research. The sooner this research is completed and the results trans-ferred to the housing industry, the better prepared the industry will be for F326. Methods for tempering out-door air and for matching ventilation rates to needs are among the most pressing problems.

The committee also hopes the announcementwill

encourage development of training manuals and cours-es based on F326.Itis understood that the Heating, Refrigeratingand Air Conditioning Institute has already undertaken such training efforts and will be updating them as F326 approaches finalization.

The Committee also hopes that manufacturers will be encouraged to begin or accelerate product develop-ment in order to proVide a wider variety of fans,

duct-ing systems, control systems and so forth, to facilitate

compliance with F326.

Finally, the committee hopes the F326 sundard can be simplified; it has been criticized as being too com-plex for use by the housing industry.

Minimum

Rates In

Each Room

There are,of course, already ventilation require-ments in the 1990 Code. How does F326 differ from them?

For a Start, F326 shares with the 1990 Code a mini-mum ventilation rate capacity of 0.3 air changes per hour (ach) for the house as a whole. However, it also specifies minimum ventilation rates (in Lis) for each

room, something the Code does not. These can total more than 0.3 ach depending on the number, type and size of rooms.

Research carried out aspartof the R-2000 program showed us that tight houses, without effective air circu-lation, can result in air quality problems in some rooms, even though the ventilation rate for the whole house is satisfactory. F326 thus includes a requirement that ven-tilation rates specified be achieved room by room. This is no problem in houses with forced-air heating -because air circulation ducts are already in place. It is more difficult, however, in houses with hydronic or baseboard heating systems.

F326 also limits the amount by which fan-supplied ventilation air can exceed fan-exhausted air. This is to avoid pressurization of the house by the ventilation

sys-tem, which can lead to problems oCinterstitial conden-sation in the building envelope. As well, it includes exact limits on the amount by which operation of the ventilation system can depressurize the house_ This

wasincluded in order to avoid pressure-induced spill-age of combustion products from heating eqUipment into the house.

Finally, it includes explicit instructions for determin-ing compliance. It generally relies on havdetermin-ing the system planned by a competent designer in accordance with recognized design principles and certification by the installer that the job has been correctly done according to the design. This means the success of the standard would depend in large part on the housing industry using competent (but not necessarily professional) HVAC designers and reliable HVAC contractors. Some Groups Haw Concerns

There have, of course, been criticisms. The strongest of these has come from the Electrical and Electronics Manufacturers' Association of Canada, which repre-sents the manufacturers of baseboard heating equip- ｾ 52

Copyright©1981 _ Renewable: Energy In Camda.

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1995 Building Code Proposols

Coli lor

Upgrllded Venli/olion SIond"rds

1

I

_,

Same Groups Have Concerns

There have, ofcourse, been criticisms, The strongest of these has come from the Electrical and Electronics Manufacturers' Association of Canada, which repre-sents the manufacturers of baseboard heating equip- ｾ S2

Copyrlghl@ 1981 - Renewable Energy In e.tnada.

room, something the Code does not. These can total more than 0.3 ach depending on the number, type and size of rooms.

Research carried out as part of the R-2000 program showed us that tight houses, without effective air circu· lation, can result in air quality problems in some rooms, even though the ventilation rate for the whole house is satisfactory. F326 thus includes a requirement that ven-tilation rates specified be achieved room by room. This is no problem in houses with forced-air heating 'because air circulation duclS are already in place, It is more diffiCUlt, however, in houses with hydronic or baseboard heating systems,

F326 also limits the amount by which fan-supplied ventilation air can exceed fan·exhausted air. This is to avoid pressurization ofthe house by the ventilation sys-tem, which can lead to problems ofinterstitial conden-sation in the building envelope. As well, it includes exact limits on the amount by which operation of the ventilation system can depressurize the house, This was included in order to avoid pressure·induced spill-age of combustion products from heating equipment into the house.

Finally, it includes explicit instructions for determin-ing compliance. It generally relies on havdetermin-ing the system planned by a competent designer in accordance with recognized design principles and certification by the installer that the job has been correctly done according tothe design. This means the success of the standard would depend in large part on the housing industry using competent (but not necessarily professional) HVAC designers and reliable HVAC COntractors. Making changes to the National Building Code (NBC)

is a careful process that often takes a long time, The 1990 version of the Code is not out yet, but work is already underway on changes for the 1995 version, One of those changes is expected to be the referencing, as mandatory, of a new CSA standard on ventilation of houses - F326 "Residential Mechanical Ventilation Requirements."

F326 defines the requirements for mechanical venti-lation systems which provide ventiventi-lation air to the liv-ing spaces of sliv-ingle-family dwellliv-ings that come under Part 9 of the NBC and which are self-contained with respect to heating, ventilating and air conditioning.

In February, the Standing Committee on Housing and Small Buildings (the committee responsible for Part 9of the NBC) agreed there is much to recommend making compliance with F326 mandatory in the 1995 NBC, although there are reServations. The Standing Commit-tee hopes that this early announcement ofits intention wiil elicit comments by those iikely to be affected and will proVide a focus and schedule for a number of

actiVities.

Among these is research on vemilation of houses, right now the mostactive area of housing research. The sooner this research is completed and the results trans-ferred to the housing industry, the better prepared the industry will be for F326. Methods for tempering out-door air and for matching ventilation rates to needs are among the most pressing problems.

The committee also hopes the announcement will encourage development of training manuals and cours-es based on F326, It is understood that the Heating, Refrigerating and Air Conditioning Institute has already undertaken such training efforts and\Viiibe updating them as F326 approaches finalization.

The Committee also hopes that manufacturers will be encouraged to begin or accelerate product develop-ment in order to provide a wider variety of fans, duct-ing systems, control systems and so forth, to facilitate compliance with F326.

Finally, the committee hopes the F326 standard can be simplified; it has been criticized as being too com-plex for use by the housing industry,

MInImum Rates In Each Room

There are. of course, already ventilation require· ments in the 1990 Code. How does F326 differ from them?

For a start, F326 shares with the 1990 Code a mini-mum ventilation rate capacity of 0.3 air changes per hour (ach) for the house as a whole. However, it also specifies minimum ventilation rates (in Lis) for each

•••

"The

｣ｯｭｭｩｴｴ･ｾ

hopes

manufacturers

will

be

encouraged to begin

or accelerau

product development,

to

comply with F326,"

•

(

JobH

C. H4:JSiOiP1r; _ l o r _ l e a l advIsortUJitb the

Codes Section, lnsttitutefor

Researeb InCLmstr-JU;tion. NationalReseareb ,Council.

Ottawa.