NATIONAL BUILDING CODE THE SUPPLEMENT

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THE SUPPLEMENT

to the

NATIONAL BUILDING CODE

of Canada

1980

Issued

by

the

Associate Committee on the National Building Code

National Research Council of Canada

Ottawa

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$7.30

NRCC No. 17724

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THE SUPPLEMENT

to the

NATIONAL BUILDING CODE

of Canada

1980

Issued by the

Associate Committee on the National Building Code

National Research Council of Canada

Ottawa

NRCC No. 17724

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First Edition 1980

©National Research Council of Canada 1980 World Rights Reserved

Printed in Canada

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v

Page

Preface ...••.•...•..••...•.•.•••..••...•..

vii

Committee Members • . . • • • • . . . . . • • . • • • • • . • . . . • . . . . . • • . .

ix

Chapter 1 Climatic Information for Building Design in Canada • . •

1

Chapter 2 Fire-Performance Ratings ••..•....•..•....•.••

23

Chapter 3 Measures for Fire Safety in High Buildings. . . . • . . . . .

59

Chapter 4 Commentaries on Part 4 of the National Building Code of

Canada 1980 . • • . . • . • . . • • . . . • . • • • . • . . . . . . •

139

Chapter 5 List of Standards Referenced in the National Building

Code of Canada 1980 .•..•..•...•.•.•....

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vii

PREFACE

The Supplement to the National Building Code 1980 contains material intended to assist the Code user in applying the Code. However, the user is not precluded from using other ap-proaches provided that they are acceptable to the authority having jurisdiction. It is published by the Associate Committee on the National Building Code.

The Supplement is made up of the following five Chapters, each of which was formerly pub-lished as an individual supplement:

Chapter No.1: Climatic InCormation Cor Building Design in Canada

This Chapter contains information on climatic loads to be expected in all parts of Canada. It is through the use of these climatic factors summarized in this Chapter, with appropriate adjust-ments for climate variation in different localities, that the Code can be used nationally.

Chapter No.2: Fire-Performance Ratings

This Chapter provides a guide to the determination of the fire resistance, flame spread and smoke-developed ratings of materials in construction in relation to the provisions of the Code. It

gives a procedure for calculating the fire-resistance rating of construction assemblies based on generic descriptions of materials used in the assemblies.

Chapter No.3: Measures Cor Fire SaCety in High Buildings

This Chapter contains material in support of the high-rise requirements in Part 3. Chapter No.4: Commentaries on Part 4

Chapter No.4 consists of explanatory material and related technical information useful to the designer in the application of the design requirements in Part 4 of the Code.

Chapter No.5: List oC Standards ReCerenced in the National Building Code 1980

Comments and inquiries on aspects of this supplement pertaining to the interpretation and use of the National Building Code should be addressed to the Secretary, Associate Committee on the National Building Code, National Research Council of Canada, Ottawa, Ontario KIA OR6. Requests for technical information of a non-Code nature are also welcome and should be di-rected to the Information Services Group, Division of Building Research, National Research Council of Canada, Ottawa, Ontario KIA OR6.

Ce document est disponible en fran~ais.

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THE ASSOCIATE COMMITTEE ON THE

NATIONAL BUILDING CODE OF CANADA

AND ITS

ST ANDING COMMITTEES

ASSOCIATE COMMITTEE ON THE NATIONAL BUILDING CODE A.G. Wilson (Chairman)

H.B. Dickens (Deputy Chairman)(4)

R. W. Anderson B.A. Bonser R.F. Buckingham S.D.C. Chutter D.E. Cornish S. Cumming R.F. DeGrace M.G. Dixon L.W. Gold J.T. Gregg R.V. Hebert D.G. Helmer J.S. Hicks

M.S. Hurst (ex officio) H.K. Jenns H.T. Jones P.M. Keenleyside(l} J. Longworth J.A. McCambly W.M. McCance R.C. McMillan J. McQuhae(l}

D.O. Monsen (ex officio) F.-X. Perreault A.R. Pitt(l} G.B. Pope R.A.W. Switzer R.T. Tamblyn D.L. Tarlton A.D. Thompson J.E. Turnbull N.G. Vokey(l) R.H. Dunn (Secretary) D.W. Boyd(3) A.T. Hansen(2)

(1) Committee term completed during preparation of 1980 Code.

(2) DBR staff who provided technical assistance to the Committee.

(3) Research Advisor (Meteorology) until December 1978.

(4) Retired October 1979. ix

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x

STANDING COMMITTEE ON USE AND OCCUPANCY(1)

G.B. Pope (Chairman) A.J.M. Aikman D.J. Boehmer RC. Burnett A.H. Cole I. Coop D.H. Featherstonhaugh E.H. Geres E.S. Hornby D.L. Lindsay(4) J.F. Berndt(3) M. Galbreath(3) A.T. Hansen(3) H.A. Locke RL. Maki A. W. McIntyre P. Mercier-Gouin I. A. Milroy(2) J. Myles RS. Nelson C.N.W. Shewan G.V. Tatham R Vassbotn J.K. Summers (Secretary)

STANDING COMMITTEE ON STRUCTURAL DESIGN(5)

J. Longworth (Chairman)

RL. Booth (Vice-Chairman)

J.F. Cutler A.G. Davenport

J . L. de Stein(2) (ex o/ficio )(6)

T. Eldridge (ex o/ficiO)(6)

V.C. Fenton P. M. Gillham(2) P.J. Harris A.C. Heidebrecht A.P. Jessome E.L. Jessop D.J. Kathol

D.J.L. Kennedy (ex o/ficiO)(6)

H.A. Krentz W.E. Lardner

N.C. LindO) (ex o/ficiO)(6)

J. G. MacGregor

C. Marsh (ex o/ficiO)(6)

V. Milligan W. Paul B.G.W. Peter E.YUzumeri R.H. Dunn (Secretary) W. R Schriever(3) D.A. Lutes(3)

(1) Responsible for Chapter 3, "Measures for Fire Safety in High Buildings." (2) Committee term completed during preparation of 1980 Code.

(4) Deceased August 1978.

(S) Responsible for Chapter 4, "Commentaries on Part 4."

(6) Representatives of CSA Materials Design Committees.

I

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STANDING COMMITTEE ON FIRE PERFORMANCE RA TINGS(l} L.W. Gold (Chairman) 1. R. Bateman A. Birkhans 1.E. Breeze 1.F. Cutler S.G. Frost 1.E. Gillespie H.labbour M.A. Kabayama 1.F. Berndt(3) M. Galbreath(3) G . W. Shorter(3) S.A. Marks P. Mercier-Gouin S.l. Murphy(2) N.S. Pearce 1. Rocheleau W. W. Stanzak(2) C.R. Thomson E.Y. Uzumeri 1.1. Shaver (Secretary)

(1) Responsible for Chapter 2, "Fire Performance Ratings."

(2) Committee term completed during preparation of 1980 Code.

xi

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CHAPTER!

CLIMATIC INFORMATION

FOR BUILDING DESIGN

IN CANADA

1 Page

Introduction . . . • . . . . . . . • . . . . . . . • . . . • . . . . . . . . • • . . . . .

3 General . . . .

3 January Design Temperatures .•....••.•..•.•..•..•.•...

4 July Design Temperatures ...•.•..•.•.••...•.••.•.•..

4 Heating Degree-Days. . . • . • . • . . . • • . . . • . . . . . . . • . • • • . . • . • .

5 Rainfall Intensity .•.•.••..•.•.•...•.••••.•.••.•.•.••.•

6 One-Day Rainfall •..••••...•..•.•.•..•.••.•.•.•.••

6 Annual Total Precipitation. . • . • . • . . . . . . • . • . • . . • . • • • . • . . • •

6 Snow Loads ... . . . .

7 Wind Effects .•.•.•....••.•••.••..•.•..••.••.•.•..•••

8 Seismic Zones • . . . . . • • . . . . • • . . . . . . . • • • • . • . • . • • . . . . . . • •

9 References • . . . • • . . • . • . • . . • . • . . • . • . • . . . . • . • • . • . • . • • . •

10 Design Data for Selected Locations in Canada. . • . . . • • • • . • . . . • • .

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3 INTRODUCTION

The great diversity of climate in Canada has a considerable effect on the performance of build-ings, consequently, their design must reflect this diversity. The purposes of this Chapter are to explain briefly how the design weather values are computed and to present recommended design data for a number of cities, towns and smaller populated places. It is through the use of such data that appropriate allowances can be made for climate variations in different localities of Canada and that the National Building Code can be applied nationally.

The design data in this Chapter are based on weather reports supplied by the Atmospheric En-vironment Service, Department of the EnEn-vironment. They have been collected and analysed, where necessary, for the Associate Committee on the National Building Code by the Depart-ment of the EnvironDepart-ment, assisted by D.W. Boyd, DepartDepart-ment of the EnvironDepart-ment Meteorolo-gist, until his retirement in December 1978. The Department has also devised appropriate meth-ods and estimated the design values for all the locations in the table of Design Data for Selected Locations in Canada where weather observations were lacking or inadequate.

As it is not practical to list values for all municipalities in Canada, recommended design weather data for locations not listed can be obtained by writing to the Energy and Industrial Ap-plications Section, Canadian Climate Centre, Atmospheric Environment Service, Environment Canada, 4905 Dufferin Street, Downsview, Ontario, M3H 5T4. It should be noted, however, that these recommended values may differ from the legal requirements set by provincial or mu-nicipal building authorities.

The information on seismic zones has been provided by the Earth Physics Branch of the De-partment of Energy, Mines and Resources. Information for municipalities not listed may be ob-tained by writing to the Seismology Division, Earth Physics Branch, Department of Energy, Mines and Resources, Ottawa, Ontario KIA OE4.

GENERAL

The choice of climatic elements tabulated in this Chapter and the form in which they are ex-pressed have been dictated largely by the requirements for specific values in several sections of the National Building Code of Canada. Heating degree-days and annual total precipitation are also included. The following notes explain briefly the significance of these particular elements in building design, and indicate what observations were used and how they were analysed to yield the required design values. To estimate design values for locations where weather observations were lacking or inadequate, the observed or computed values for the weather stations were plot-ted on large-scale maps. Isolines were drawn on these working charts to show the general distri-bution of the design values.

In the table, design weather data are listed for over 600 locations, which have been chosen for a variety of reasons. Incorporated cities and towns with populations of over 5 000 have been in-cluded unless they are close to other larger cities. For sparsely populated areas many smaller towns and villages have been listed. The design weather data for weather stations themselves are the most reliable and hence these stations have often been listed in preference to locations with somewhat larger populations. A number of requests for recommended design weather data for other locations have been received, and where most of the elements were estimated, they were also added to the list. In some cases the values obtained from the large-scale charts have not been rounded off.

As previously noted in the Introduction to this Chapter, Environment Canada will estimate data for locations not listed in the table using the list of observed or computed values for weather stations, the large-scale manuscript charts and any other relevant information that is available. In the absence of weather observations at any particular location, a knowledge of the local to-pography may be important. For example, cold air has a tendency to collect in depressions, pre-cipitation frequently increases with elevation and winds are generally stronger near large bodies of water. These and other relationships affect the corresponding design values and will be taken into consideration where possible in answering inquiries.

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4

All the weather records that were used in preparing the table were, of necessity, observed at inhabited locations, and hence interpolations from the charts or the tabulated values will apply only to locations at similar elevations and with similar topography. This is particularly significant in mountainous areas where the values apply only to the populated valleys and not to the moun-tain slopes and high passes, where, in some cases, very different conditions are known to exist. JANUARY DESIGN TEMPERATURES

A building and its heating system should be designed to maintain the inside temperature at some pre-determined leveL To do this it is necessary to know the most severe weather conditions under which the system will be expected to function satisfactorily. Failure to maintain the inside temperature at the pre-determined level will not usually be serious if the temperature drop is not great and if the duration is not long. The outside conditions used for design should, therefore, not be the most severe in many years, but should be the somewhat less severe conditions that are occasionally but not greatly exceeded.

Winter design temperature is based on an analysis of winter air temperatures only. Wind and solar radiation also affect the inside temperature of most buildings, but there is no convenient way of combining their effects with that of outside air temperature. Some quite complex meth-ods of taking account of several weather elements have been devised and used in recent years, but the use of average wind and radiation conditions is usually satisfactory for design purposes.

The winter design temperature is defined as the lowest temperature at or below which only a certain small percentage of the hourly outside air temperatures in January occur. In previous is-sues of these climatic data the January design temperatures were obtained from a tabulation of hourly temperature distributions for the 10 year period 1951 to 1960 for 118 stations. Hourly data summaries{}) (which include temperature frequency distributions) based on the 10 year period 1957 to 1966 have been published for several stations each year since 1967 and are now available for 109 stations. They provide a second set of January design temperatures. For the 69 stations that appeared in both lists, the current design temperature is the average of these 2, and is, therefore, based on the 16 year period 1951 to 1966 with a 4 year overlap. For the 89 stations that appeared in only 1 of the lists, the design temperatures were adjusted to make them more con-sistent.

The January design temperatures for all the other locations in the table are estimates, and, where necessary, have been adjusted to make them more representative of the 16 year period. Most of the adjustments were less than one Celsius degree and only about 16 exceeded 1%°.

The adjustments mentioned above are an indication of the variation in the design temperature from one decade to another. The design temperatures for the next 20 or 30 years may differ from the tabulated values by 1 or 2 Celsius degrees and, of course, the year to year variation will be much greater. Most of the temperatures were observed at airports. Design values for the core areas of some large cities could be a degree or two milder, but values for the fringe areas are probably about the same as for the airports. No adjustments have been made, therefore, for the city effect.

The 21/2 per cent January design temperature is the value ordinarily used in the design of heat-ing systems. In special cases when the control of inside temperature is more critical, the 1 per cent value may be used.

JULY DESIGN TEMPERATURES

A building and its cooling and dehumidifying system should be designed to maintain the inside temperature and humidity at certain pre-determined levels. To do this it is necessary to know the most severe weather conditions under which the system will be expected to function satisfactori-ly. Failure to maintain the inside temperature and humidity at the pre-determined levels will usu-ally not be serious if the increases in temperature and humidity are not great and if the duration is not long. The outside conditions used for design should, therefore, not be the most severe in many years, but should be the somewhat less severe conditions that are occasionally but not greatly exceeded.

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5

The summer design temperatures in this Chapter are based on an analysis of July air tempera-tures and humidities only. Wind and solar radiation also affect the inside temperature of most buildings and may in some cases be of more importance than the outside air temperature. It seems, however, that no method of allowing for variations in radiation has yet become generally accepted. When requirements have been standardized, it may be possible to provide more com-plete weather information for summer conditions, but in the meantime only dry-bulb and wet-bulb design temperatures can be provided.

The frequency distribution of combinations of dry-bulb and wet-bulb temperatures for each month from June to September have been tabulated for 33 Canadian weather stations by Boughner.(2) If the summer dry-bulb and wet-bulb design temperatures are defined as the tem-peratures that are exceeded 2% per cent of the hours in July, then design values can be obtained directly for these 33 stations.

The dry-bulb design temperatures in previous editions of this Chapter were based on the val-ues for these 33 stations and a relationship between the design temperatures and the mean an-nual maximum temperatures. Hourly data summaries(l) (which include temperature frequency distributions) based on the 10 year period 1957 to 1966 are now available for 109 stations. They provide a second set of July bulb design temperatures. For the 109 stations the current dry-bulb temperatures are the averages of the values in these 2 sets. For all the other locations in the table the previous values have been adjusted to make them consistent with the calculated values. The adjustments exceeded one Celsius degree in only about 20 cases. AU values were converted to degrees Celsius and rounded off to the nearest degree.

The July wet-bulb design temperatures have been obtained in the same way, with one excep-tion. The previous values were obtained directly for the 33 stations in Boughner's publication,(2) and all the rest were estimated from these 33 without using any intermediate statistic. The cur-rent values for the 109 stations with hourly data summaries are averages between the previous values and the values from the hourly data summaries. For all the other locations the previous values have been adjusted to make them consistent. The adjustments exceed one Celsius degree in only 6 cases. All wet-bulb values were converted to degrees Celsius and rounded off to the nearest degree.

HEATING DEGREE-DAYS

It has long been known that the rate of consumption of fuel or energy required to keep the in-terior of a small building at 21°C when the outside air temperature is below 18°C is roughly pro-portional to the difference between 1SoC and the outside temperature. Wind speed, solar radia-tion, the extent to which the building is exposed to these elements and the internal heat sources also affect the heat required, but there is no convenient way of combining these effects. For av-erage conditions of wind, radiation, exposure and internal sources, however, the proportionality with the temperature difference still holds. Heating degree-days based on temperature alone are, therefore, still useful when more complex methods of calculating fuel requirements are not feasi-ble.

Since the fuel required is also proportional to the duration of cold weather, a convenient method of combining these elements of temperature and time is to add the differences between 1SoC and the mean temperature for every day in the year when the mean temperature is below 1S°C. It is assumed that no heat is required when the mean outside air temperature for the day is 1SoC or higher.

For about two-thirds of the locations listed, degree days below 18°C have been computed day by day for the length of record available over the period 1941 to 1970, and an average annual to-tal determined and published by the Atmospheric Environment Service. (3) These values are given in the table to the nearest degree day.

For all the other locations in the table the degree-days below 65°F in the previous edition of this Chapter were converted to degree-days below 1SoC and rounded off to the nearest 10 de-gree-days. Adjustments ranging from SO to 120 Celsius degree-days were made to allow for the differences between 65°F and 1SoC. These degree-day values were then adjusted to make them consistent with the computed values.

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A difference of only one Celsius degree in the annual mean temperature will cause a differ-ence of 250 to 350 in the Celsius degree-days. Since differdiffer-ences of half a degree in the annual mean temperature are quite likely to occur between 2 stations in the same city or town, it is obvi-ous that heating days can not be relied on to an accuracy of less than about 100 degree-days.

RAINF ALL INTENSITY

Roof drainage systems are designed to carry off the rainwater from the most intense rainfall that is likely to occur. A certain amount of time is required for the rainwater to flow across or down the roof before it enters the gutter or drainage system. This results in the smoothing out of the most rapid changes in rainfall intensity. The drainage system, therefore, need cope only with the flow of rainwater produced by the average rainfall intensity over a period of a few minutes which can be called the concentration time.

In Canada it has been customary to use the 15 min rainfall that will probably be exceeded on the average once in 10 years. The concentration time for small roofs is much less than 15 min and hence the design intensity will be exceeded more frequently than once in 10 years. The safety factors included in the tables in the ACNBC Canadian Plumbing Code will probably reduce the frequency to a reasonable value and, in addition, the occasional failure of a roof drainage system will not be particularly serious in most cases.

The rainfall intensity values tabulated in the previous edition of this Chapter were based on measurements of the annual maximum 15 min rainfalls at 139 stations with 7 or more years of record. They were the 15 min rainfalls that would be exceeded once in 10 years on the average, or the values that had 1 chance in 10 of being exceeded in any 1 year.

It is very difficult to estimate the pattern of rainfall intensity in mountainous areas where pre-cipitation is extremely variable. The values in the table for British Columbia and some adjacent areas are mostly for locations in valley bottoms or in extensive, fairly level areas. Much greater intensities may occur on mountain sides.

ONE DAY RAINFALL

-If for any reason a roof-drainage system becomes ineffective, the accumulation of rainwater may be great enough in some cases to cause a significant increase in the load on the roof. Al-though the period during which rainwater may accumulate is unknown, it is common practice to use the maximum 1 day rainfall for estimating the additional load.

For most weather stations in Canada the total rainfall for each day is published. The maximum "1 day" rainfall (as it is usually called) for several hundred stations has been determined and published by the Atmospheric Environment Service. (4) Since these values are all for predeter-mined 24 h periods, beginning and ending at the same time each morning, it is probable that most of them have been exceeded in periods of 24 h including parts of 2 consecutive days. The maximum "24 h" rainfall (i.e. any 24 h period) according to Hershfield and Wilson is, on the av-erage, about 113 per cent of the maximum "1 day" rainfall. (5)

Most of the 1 day rainfall amounts in the table have been copied directly from the latest edi-tion of Climatic Normals.(4) Values for the other locaedi-tions have been estimated. These maximum values differ greatly within relatively small areas where little difference would be expected. The variable length of record no doubt accounts for part of this variability, which would probably be reduced by an analysis of annual maxima instead of merely selecting the maximum in the period of record.

ANNUAL TOTAL PRECIPITATION

The total amount of precipitation that normally falls in 1 year is frequently used as a general indication of the wetness of a climate. As such it is thought to have a place in this Chapter. Total precipitation is the sum in millimetres of the measured depth of rainwater and lAo of the mea-sured depth of snow (since the average density of fresh snow is about lAo that of water).

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Most of the average annual total precipitation amounts in the table have been copied directly from the latest edition of Climatic Normals(4) where averages for the 30 year period 1941 to 1970

have been tabulated. For all other locations the values have been estimated.

SNOW LOADS

The roof of a building should be able to support the greatest weight of snow that is likely to ac-cumulate on it. Some observations of snow loads on roofs have been made in Canada, but they are not sufficiently numerous to form the basis for estimating snow loads throughout the country. Similarly, observations of the weight or water equivalent of the snow on the ground are inade-quate. The observations of roof loads and water equivalents are very useful, as noted below, but the basic information for a consistent set of snow loads must be the measured depth of snow on the ground.

The estimation of the design snow load on a roof from snow depth observations involves the following steps:

1. The depth of snow on the ground which will be equalled or exceeded once in 30 years, on the average, is computed.

2. A density is assumed and used to convert snow depths to loads.

3. An adjustment is added to allow for the increase in the load caused by rainwater ab-sorbed by the snow.

4. Because the accumulation of snow on roofs is often different from that on the ground, certain adjustments should be made to the ground snow load to provide a design snow load on a roof.

These steps are explained in more detail in the following paragraphs.

The annual maximum depths of snow on the ground for periods ranging from 5 to 31 years are now available for about 480 stations. Many of these have such short records that they cannot be considered reliable, but on the other hand they cannot be ignored. About a quarter of the sta-tions have records of at least 20 years which is much more information than was used for previ-ous estimates of snow loads. These data were assembled and analysed using Gumbel's extreme value method as explained by Boyd. (6) The resulting values are the snow depths which will

prob-ably be exceeded once in 30 years on the average, or which have a probability of 1 in 30 of being exceeded in any 1 year.

The specific gravity of old snow generally ranges from 0.2 to 0.4 times that of water. It is usu-ally assumed in Canada that 0.1 is the average specific gravity of new snow. The 30 year maxi-mum snow depth will almost certainly occur immediately after an unusually heavy snowfall, and hence a large proportion of the snow cover will have a low density. It therefore seemed reason-able to assume a mean specific gravity under these unusual circumstances of 0.2 for the whole snow cover.

Because the heaviest loads in Canada frequently occur when early spring rain adds to an al-ready heavy snow load, it was considered advisable to increase the snow load by the load of rain-water that it might retain. It is convenient to use the maximum 1 day rainfall in the period of the year when snow depths are greatest. Boyd has explained how a 2 or 3 month period was selected.(6)

The results from a survey of several winters of snow loads on roofs indicated that average roof loads were generally much less than loads on the ground. The conditions under which the design snow load on the roof may be taken as 80 or 60 per cent of the ground snow load are given in Section 4.1 of the National Building Code 1980. The Code also permits further decreases in de-sign snow loads for steeply sloping roofs, but requires substantial increases for roofs where snow accumulation may be more rapid. Recommended adjustments are given in Chapter 4.

The ground snow loads computed in kilonewtons per square metre were all plotted on maps as an aid in estimating values for the other locations listed in the table. All values are tabulated to the nearest tenth of a kilonewton per square metre but some may be in error by 10 per cent.

Tabulated values cannot be expected to indicate all the local differences in ground snow loads, even where these are known to exist. The values in the table are intended to apply only to the

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8

area within a town or village and not necessarily to extended areas such as townships. This fact is particularly important in mountainous areas where much higher snow loads often occur on mountain slopes or high passes.

WIND EFFECTS

All structures should be built to withstand the pressures and suctions caused by the strongest gust of wind that is likely to blow at the site in many years. For many buildings this is the only wind effect that needs to be considered, but tall or slender structures should also be designed to limit their vibrations to acceptable levels. Wind induced vibrations may require several minutes to build up to their maximum amplitude and hence wind speeds averaged over several minutes or longer should be used for design. The hourly average wind speed is the value available in Cana-da.

The provision of "velocity pressures" for both average wind speeds and gust speeds for esti-mating pressures, suctions and vibrations involves the following steps:

1. The annual maximum hourly wind speeds were analysed to obtain the hourly wind speeds that will have 1 chance in 10,30 and 100 of being exceeded in any 1 year.

2. An average air density was assumed in order to compute the "velocity pressures" for the hourly wind speeds.

3. A value of 2 was assumed for the "gust effect factor" to compute the "velocity pres-sures" for the gust speeds.

The actual wind pressure on a structure increases with height and varies with the shape of the structure. The factors needed to allow for these effects are tabulated in Section 4.1 of the Na-tional Building Code of Canada 1980 and in Chapter 4. The other 3 steps are discussed in more detail in the following paragraphs.

Until recently the only wind speed record kept at a large number of wind-measuring stations in Canada was the number of miles of wind that pass an anemometer head in each hour, or the hourly average wind speed. Many stations are now recording only spot readings of the wind speed each hour, and these may have to be used for design at some future time. For the present, however, the older hourly mileages are the best data on which to base a statistical analysis. The annual maximum hourly mileages for over 100 stations for periods from 10 to 22 years were ana-lysed using Gumbel's extreme value method to calculate the hourly mileages that would have one chance in 10,30 and 100 of being exceeded in any 1 year.

Values of the "1 in 30" hourly mileages for the additional 500 locations in the table have been estimated. To obtain the "1 in 10" and "1 in 100" values for these locations it was necessary to estimate the value of the parameter 1Ia which is a measure of the dispersion of the annual maxi-mum hourly mileages. The 100 known values were plotted on a map from which estimates of 1Ia were made for the other locations. Knowing the "1 in 30" hourly mileages and the values of 1Ia,

the "1 in 10" and "I in 100" values could be computed.

Pressures, suctions and vibrations caused by the wind depend not only on the speed of the wind but also on the air density and hence on the air temperature and atmospheric pressure. The pressure, in turn, depends on elevation above sea level and varies with changes in the weather systems. If V is the design wind speed in miles per hour, then the velocity pressure, P, in pounds per square foot is given by the equation

P CV2

where C depends on air temperature and atmospheric pressure as explained in detail by Boyd. (7) The value 0.0027 is within 10 per cent of the monthly average value of C for most of Canada in the windy part of the year. This value (0.0027) has been used to compute all the velocity pres-sures corresponding to the hourly mileages with annual probabilities of being exceeded of 1/10, 1/30 and 11100. The pressures were then converted from psfto kN/m2 _{and are shown in the table}

in columns headed only by the numerical values of the probabilities.

The National Building Code requires the design gust pressures for structural elements to be twice the corresponding hourly pressures in the table. Because wind speeds are squared to get pressures, this statement is equivalent to saying that the gust factor is the square root of 2.

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9

For buildings over 12 m high, the gust velocity pressures and suctions must be increased ac-cording to a table in Section 4.1 of the National Building Code of Canada 1980 which is based on the assumption that the gust speed increases in proportion to the lAo power of the height. The av-erage wind speeds used in computing the vibrations of a building are more dependent on the roughness of the underlying surface. A method of estimating their dependence on roughness and height is given in Chapter 4.

The calculations for building vibrations in Chapter 4 have been drawn up for wind speeds mea-sured in metres per second. The equation

P = CV2

could be used to convert the tabulated pressures to wind speeds provided the constant C was converted to SI units. If P is in newtons per square metre and V in metres per second, the value of C would be 0.64689. In SI units, however, the equation can be written in the form

P ljz p V2

where p is the air density in kglm3_•_{The density of dry air at O°C and the standard atmospheric}

pressure of 101.325 kPa is 1.2929 kglm3_•_{Half this value, or 0.64645, is very close to the}

con-verted value of C. The difference (less than 1 in 1 000) is negligible and therefore the density of air at O°C and standard atmospheric pressure has been adopted for converting wind pressures to wind speeds. The following table has been arranged to give speeds to the nearest mls for all pres-sures appearing in the main table. The value "P" is assumed to be equal to 0.00064645V2.

CONVERSION OF WIND PRESSURES TO WIND SPEEDS

P V P V P V kN/m1 _mls _kN/m1 _mls _kN/m1 _mls .14 to .15 15 .46 to .48 27 .96 to 1.00 39 .16 to .17 16 .49 to .52 28 1.01 to 1.06 40 .18to.19 17 .53 to .56 29 1.07 to 1.11 41 .20 to .22 18 .57 to.6O 30 1.12 to 1.16 42 .23 to .24 19 .61 to .64 31 1.17 to 1.22 43 .25 to .27 20 .65 to .68 32 1.23 to 1.28 44 .28 to .29 21 .69 to .72 33 1.29 to 1.33 45 .30 to .32 22 .73 to .76 34 1.34 to 1.39 46 .33 to .35 23 .77 to .81 35 1.40 to 1.45 47 .36 to .38 24 .82 to .86 36 1.46 to 1.52 48 .39 to .42 25 .87 to .90 37 1.53 to 1.58 49 .43 to .45 26 .91 to .95 38 1.59 to 1.64 50 SEISMIC ZONES

The parameter in establishing the seismic zones is AlOO defined as the ground acceleration that has an annual probability of being equalled or exceeded of 1 in 100. (8) The zones are based on the

statistical computer analysis of past earthquakes throughout the country for this century. (10) It is corroborated by the results from a larger but less reliable seismic sample dating back to 1638.(9) The assigned zones reflect the opinion of experts in the fields of seismology, geology and engi-neering from industry, government and universities comprising members of the Canadian Na-tional Committee on Earthquake Engineering and various relevant committees responsible to the Associate Committee on the National Building Code.

The zones and the assigned horizontal design ground acceleration ratio, A, for each zone, as a fraction of gravitational acceleration, are shown in the table. The zone boundaries in terms of A100 are shown in Table 1-2 of the Commentary on Effects of Earthquakes. (8)

In the Arctic Region and other parts of the Northwest Territories, there are insufficient data for a statistical study. The zone boundaries have been established by the seismologists of the De-partment of Energy, Mines and Resources from their knowledge of earthquake activity in these areas.

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10 REFERENCES

(1) Hourly Data Summaries. Dept. of Transport, Meteorological Branch and later Dept. of the Environment, Atmospheric Environment Service, various dates from May 1967 to March 1974.

(2) Boughner,

c.c.

Percentage Frequency of Dry- and Wet-bulb Temperatures from June to September at Selected Canadian Cities. Dept. of Transport, Meteorological Branch, Canadian Meteorological Memoirs, No.5, Toronto, 1960.

(3) Aston, D. Degree Days 1941-1970. Dept. of the Environment, Atmospheric Environ-ment Service, Downsview, Ontario, 1977 and 1978 (8 Climatic Data Sheets).

(4) Canadian Normals, Vol. 2-SI, Precipitation 1941-1970. Dept. of the Environment, Atmo-spheric Environment Service, Downsview, Ontario, 1975.

(5) Hershfield, D.M. and Wilson, W.T. Generalizing Rainfall Intensity - Frequency Data. International Association of Scientific Hydrology, General Assembly, Toronto, Vol. 1, 1957, pp. 499-506.

(6) Boyd, D.W. Maximum Snow Depths and Snow Loads on Roofs in Canada. Proceedings, 29th Annual Meeting, Western Snow Conference, Spokane, Wash., April 1961.

(7) Boyd, D. W. Variations in Air Density over Canada. National Research Council of Cana-da, Division of Building Research, Technical Note No. 486, June 1967.

(8) Commentary on Effects of Earthquakes, Chapter 4 of the Supplement to the National Building Code of Canada 1980.

(9) Milne, W.G. and Davenport, A.G. Distribution of Earthquake Risk in Canada, Bulletin of Seismological Society of America, Vol. 59, No.2, pp. 729-754, April 1969, also Fourth World Conference on Earthquake Engineering, Santiago, Chile, January, 1969.

(10) Whitham, K., Milne, W.G. and Smith, W.E.T. The New Seismic Zoning Map for

Cana-da, 1970 Edition, The Canadian Underwriter, June 1970.

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11

DESIGN DATA FOR SELECTED LOCATIONS IN CANADA Design Temperature

Hourly Wind Seismic

Province January July 2%% Degree 15 One Ann. Gnd. Pressures Data

and Days Min. Day Tot. Snow

Location _{2%%, 1%, Dry, Wet,} Below Rain., Rain., Pcpn.,

~~~~

Acceler-18"C mm mm mm 1110,

_JZ~2

~~~~

·C ·C ·C ·C kN/m2 Zone ation Ratio, A British Columbia -10 -11 29 20 3148 10 83 1502 2.4 0.42 0.55 0.71 3 0.08 Abbotsford ...

~r::!::::::::::::::::::::::::

-13 -15 31 20 2950 8 116 1648 3.1 0.55 0.75 1.00 2 0.04 -5 -7 31 18 3160 10 125 2019 2.6 0.47 0.58 0.70 3 0.08 Ashcroft ... -25 -28 34 20 3687 10 45 224 1.3 0.28 0.35 0.43 1 0.02 Beaton River ... -37 -39 25 18 7068 13 SO 435 3.2 0.22 0.27 0.34 1 0.02 BumsLake ... -30 -33 25 17 5801 10 48 513 2.5 0.30 0.36 0.43 2 0.04 Cache Creek ... -25 -28 34 20 3800 10 63 250 1.4 0.29 0.35 0.43 1 0.02 Campbell River ... -7 -9 26 18 3417 10 105 1539 2.8 0.46 0.58 0.72 3 0.08 Carmi ... ··· -24 -26 33 20 5191 10 98 563 3.4 0.24 0.33 0.44 1 0.02 Casdegar ... -19 -22 32 20 3751 10 51 710 3.4 0.23 0.30 0.39 0 0 Chetwynd ... -35 -38 27 18 6100 15 63 410 2.2 0.32 0.37 0.44 1 0.02 Chilliwack ... -12 -13 30 20 2932 8 122 1741 2.8 0.48 0.63 0.83 2 0.04 Cloverdale ... -8 -10 29 20 3080 8 102 1270 2.1 0.46 0.58 0.72 3 0.08 Comox ... -7 -9 27 18 3203 10 113 1206 2.5 0.45 0.58 0.74 3 0.08 Courtenay ... -7 -9 28 18 3205 10 103 1452 2.5 0.45 0.58 0.74 3 0.08 Cranbrook ... -27 -30 32 19 4762 10 43 438 2.4 0.22 0.29 0.37 0 0 Crescent Valley ... -20 -23 31 19 4228 10 52 786 3.4 0.22 0.29 0.37 0 0 Crofton ... -6 -8 28 18 2850 8 76 1029 2.0 0.48 0.58 0.69 3 0.08 Dawson Creek ... -36 -39 27 18 6152 18 67 425 2.0 0.31 0.37 0.44 1 0.02 DogCreek ... -28 -30 29 18 5207 10 47 393 1.9 0.31 0.37 0.44 1 0.02 Duncan ... -6 -8 29 18 2907 8 110 1043 2.0 0.48 0.58 0.69 3 0.08 Elko ... -28 -31 29 19 4379 13 54 580 3.5 0.27 0.37 0.50 0 0 Fernie ... -29 ·32 29 19 4970 13 106 1082 4.6 0.33 0.43 0.55 0 0 Fort Nelson ... -40 -42 28 18 7064 13 81 446 2.4 0.19 0.24 0.29 1 0.02 Fort St. John ... -36 -38 26 18 6118 15 80 450 2.5 0.31 0.36 0.42 1 0.02 Glacier ... -27 -30 27 17 5799 10 71 1493 7.6 0.24 0.29 0.35 1 0.02 Golden ... -28 -31 29 17 4869 8 59 473 3.8 0.27 0.32 0.38 0 0 Grand Forks ... -20 -22 35 20 4037 10 41 450 2.0 0.26 0.36 0.48 1 0.02 Greenwood ... -20 -22 35 20 4506 10 107 478 1.9 0.29 0.39 0.52 1 0.02 Haney ... -9 -11 30 20 2946 10 117 1926 2.3 0.47 0.60 0.77 3 0.08 Hope ... ·16 -18 32 20 3128 8 106 1601 3.4 0.41 0.55 0.73 2 0.04 Kamloops ... -25 -28 34 20 3755 13 57 268 1.8 0.30 0.37 0.45 1 0.02 Kaslo ... -23 -26 29 19 4070 10 51 785 3.0 0.22 0.28 0.36 0 0 Kelowna ... ·17 -20 33 20 3647 10 64 320 1.9 0.34 0.43 0.53 1 0.02 Kimberley ... ·26 -29 31 19 4840 10 49 378 3.0 0.22 0.29 0.37 0 0 Kitimat Plant ... -16 -18 23 16 4103 13 185 2826 3.5 0.22 0.26 0.31 3 0.08 Kitimat Townsite ... -16 -18 23 16 4187 13 119 2377 4.5 0.22 0.26 0.31 3 0.08 Langley ... -8 -10 29 20 3127 8 118 1501 2.2 0.45 0.58 0.73 3 0.08 Lillooet ... -23 ·25 33 20 4000 10 114 391 2.5 0.32 0.39 0.49 1 0.02 Lytton ... -19 -22 35 20 3239 10 77 463 3.0 0.31 0.39 0.49 1 0.02 Mackenzie ... -35 -38 26 17 6150 10 63 430 3.6 0.24 0.29 0.35 1 0.02 McBride ... ·34 -37 30 18 4938 13 SO 525 3.4 0.27 0.32 0.38 1 0.02 McLeod Lake ... -35 ·37 27 17 5867 10 63 460 2.5 0.24 0.29 0.35 1 0.02 Masset ... -7 -9 17 15 3726 13 76 1409 1.8 0.49 0.58 0.68 3 0.08 Merrit ... ·26 -29 34 20 4325 8 57 254 2.0 0.32 0.39 0.49 1 0.02 Mission City ... -9 -11 30 20 2956 13 98 1573 2.4 0.47 0.60 0.77 3 0.08 Montrose ... -17 ·20 32 20 4080 10 51 630 3.2 0.22 0.30 0.41 0 0 Nakusp ... -24 -27 31 19 4037 10 51 790 3.6 0.24 0.30 0.37 0 0 Nanaimo ... -7 -9 26 18 3304 8 92 1085 2.6 0.47 0.58 0.71 3 0.08 Nelson ... -20 -24 31 19 3669 10 66 763 3.3 0.22 0.29 0.37 0 0 New Westminster ... -8 -10 29 19 2948 10 132 1520 2.1 0.44 0.55 0.68 3 0.08 North Vancouver ... -7 -9 26 19 3090 10 100 1791 2.2 0.44 0.55 0.68 3 0.08 Ocean Falls ... -12 -14 23 16 3499 13 234 4390 3.0 0.47 0.55 0.65 3 0.08 100 Mile House ... -28 -31 30 18 4500 10 51 460 2.6 0.30 0.36 0.43 1 0.02 OSOyoos ... -16 -18 33 20 3295 10 35 342 1.4 0.30 0.43 0.59 1 0.02 Penticton ... -16 -18 33 20 3513 10 45 296 1.3 0.40 0.52 0.68 1 0.02 Port Albemi ... -5 -7 31 18 3312 10 140 2009 2.6 0.47 0.58 0.70 3 0.08 Port Hardy ... -5 ·7 20 16 3659 13 131 1730 2.1 0.49 0.58 0.68 3 0.08 Port McNeill ... ·5 ·7 22 17 3480 13 127 1270 2.4 0.49 0.58 0.68 3 0.08 Powell River ... -9 -11 26 18 3307 8 80 1017 2.4 0.42 0.55 0.71 3 0.08 Column 1 3 4 5 6 7 8

[C

10 11 12 13 14 15

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p

12

DESIGN DATA FOR SELECTED LOCATIONS IN CANADA

I

Design Temperature

Hourly Wind Seismic

Province January July 2112% Degree 15 One

AM.i

God. Pressures Data

Location _{2112%, 1%, Dry, Wet,} Below Rain., Rain., _18·C _mm _mm

P:~"I~~~~

_1110,

I

Acceler-ki2~2 ~~~~

Zone ation

·C ·C ·C ·C kN/m2 Ratio, A Prince George ... -33 -36 28 18 5387 15 50 621 2.6 0.25 0.30 0.36 1 0.02 Prince Rupert ... -14 ·16 19 15 4383 13 141 2415 2.6 0.42 0.50 0.59 3 0.08 Princeton ... ·27 -30 32 20 4554 10 37 359 2.3 0.24 0.32 0.42 1 0.02 Qualicum Beach ... ·7 ·9 27 18 3205 10 102 1270 2.6 0.46 0.58 0.72 3 0.08 Quesnel ... ·33 ·35 30 17 4733 10 72 514 2.7 0.25 0.29 0.34 1 0.02 Revelstoke ... ·26 ·29 32 19 4073 13 78 1096 4.6 0.24 0.29 0.35 2 0.04 Richmond ... ·7 ·9 27 19 2920 8 114 1450 1.9 0.45 0.55 0.67 3 0.08 Salmon Arm ... ·23 ·26 33 20 3894 13 43 531 2.8 0.29 0.35 0.43 1 0.Q2 Sandspit ... -6 ·7 15 15 3681 13 80 1261 2.3 0.54 0.63 0.74 3 0.08 Sidney ... ·6 -8 26 18 2800 8 102 790 1.6 0.46 0.55 0.66 3 0.08 Smithers ... ·29 ·31 25 17 5305 13 60 502 2.2 0.31 0.37 0.44 2 0.04 Smith River ... -46 ·48 26 17 7652 8 68 465 2.8 0.19 0.25 0.33 2 0.04 Squamish ... ·11 ·13 29 20 3314 10 112 2061 3.2 0.38 0.50 0.65 3 0.08 Stewart ... ... ·23 -25 23 16 4701 13 178 1843 8.4 0.32 0.39 0.48 3 0.08 Taylor ... ·36 ·38 26 18 6100 15 56 398 2.5 0.32 0.37 0.44 1 0.02 Terrace ... -20 ·22 25 16 4429 13 117 1200 5.1 0.36 0.43 0.51 2 0.04 Tofino ... -2 ·4 19 16 3217 13 174 3061 2.5 0.54 0.63 0.74 3 0.08 Trail. ... -17 ·20 33 20 3639 10 51 664 3.2 0.17 0.24 0.33 0 0 UcIuelet ... ·2 ·4 19 16 3180 13 140 2690 2.4 0.54 0.63 0.74 3 0.08 Vancouver ... ·7 ·9 26 19 3005 10 94 1324 1.9 0.45 0.55 0.67 3 0.08 Vernon ... ·20 -23 33 20 3838 13 40 393 2.0 0.32 0.39 0.49 1 0.02 Victoria ... ·5 ·7 24 17 3075 5 81 657 1.5 0.48 0.58 0.70 3 0.08 Williams Lake ... ·31 -34 29 17 4625 10 37 402 2.9 0.30 0.35 0.41 1 0.02 Youbou ... -5 ·7 31 19 2942 10 114 1650 2.5 0.46 0.55 0.66 3 0.08 Alberta Athabasca ... -35 -38 28 19 6310 18 88 442 2.2 0.30 0.37 0.45 0 0 Banff ... ·30 -32 27 17 5719 18 53 477 2.8 0.39 0.45 0.52 0 0 Barrhead ... -34 ·37 28 19 6000 20 102 460 2.2 0.32 0.39 0.49 0 0 Beaverlodge ... -35 -38 28 18 5909 25 101 455 2.1 0.27 0.33 0.40 0 0 Brooks ... ·32 ·34 32 19 5266 18 89 353 1.6 0.39 0.48 0.57 0 0 Calgary ... -31 ·33 29 17 5344 23 95 437 0.9 0.40 0.46 0.54 0 0 Campsie ... -34 -37 28 19 6080 20 111 445 2.3 0.32 0.39 0.49 0 0 Cam rose -33 ·35 29 19 5960 20 92 394 1.7 0.21 0.29 0.39 0 0 Cardson ... -30 ·33 29 18 4870 20 102 495 1.8 0.74 0.93 1.15 0 0 Claresholm ... , ... -31 -34 29 18 4782 15 97 460 1.0 0.66 0.80 0.96 0 0 Cold Lake -36 ·38 28 20 6183 15 94 433 1.5 0.31 0.37 0.44 0 0 Coleman ... ·31 -34 28 18 5418 15 62 537 2.6 0.54 0.69 0.87 0 0 Coronation ... ·31 ·33 30 19 5905 20 99 373 1.9 0.23 0.32 0.43 0 0 Cowley ... ·31 ·34 29 18 5189 15 74 504 1.7 0.73 0.91 1.13 0 0 Drumheller ... -31 -33 29 18 5330 20 73 358 1.6 0.32 0.39 0.49 0 0 Edmonton ... -32 ·34 28 19 5590 23 114 446 1.5 0.32 0.40 0.51 0 0 Edson ... -34 ·37 28 18 5962 18 79 554 2.4 0.36 0.43 0.50 0 0 Embarras Portage ... -41 -44 27 19 6999 10 82 399 1.6 0.31 0.37 0.45 0 0 Fairview ... -38 -40 27 18 6152 15 64 422 2.1 0.26 0.32 0.39 0 0 Fort McMurray ... ·39 ·41 28 19 6779 13 61 435 1.8 0.27 0.32 0.38 0 0 Fort Saskatchewan ... -32 -35 28 19 5881 20 78 430 1.5 0.31 0.39 0.49 0 0 Fort Vermilion ... ·41 ·43 28 18 7077 13 60 360 2.0 0.22 0.26 0.32 0 0 Grande Prairie ... ·36 -39 27 18 6144 23 78 442 2.1 0.37 0.44 0.52 0 0 Habay ... ·41 ·43 28 18 7050 13 63 360 2.5 0.20 0.24 0.28 0 0 Hardisty ... -33 ·35 30 19 5950 20 56 384 1.8 0.24 0.32 0.42 0 0 High River. ... ·31 -33 28 17 5414 18 111 489 1.9 0.51 0.60 0.72 0 0 Jasper ... ·32 -35 28 18 5530 10 108 402 2.4 0.37 0.43 0.50 0 0 Keg River ... ·40 -42 28 18 6854 13 60 403 2.6 0.19 0.24 0.29 0 0 Lac La Biche.. ... -35 -38 28 19 6308 15 82 460 2.1 0.31 0.37 0.44 0 0 Lacombe ... -33 -35 29 18 5761 23 71 456 1.8 0.24 0.31 0.40 0 0 Lethbridge ... -30 -33 31 18 4717 20 93 436 1.5 0.64 0.76 0.91 0 0 Manning ... ·39 ·41 27 18 6600 13 51 360 2.5 0.21 0.26 0.32 0 0 Medicine Hat ... ·31 ·34 33 19 4872 23 122 348 1.4 0.39 0.49 0.60 0 0 Peace River ... -37 ·40 27 18 6424 15 48 351 2.4 0.24 0.29 0.36 0 0 Penhold ... ... ·32 -35 i 29 18 5845 23 124 449 1.5 0.31 0.37 0.44 0 0 I Column 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

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13

DESIGN DATA FOR SELECTED LOCATIONS IN CANADA

Design Temperature Hourly Wind Seismic

Province and Location

~ Degree 1~ One Ann. Ond. Pressures Data

~ Days Mm. Day Tot. Snow !---;----r----+----,---~

Below Rain., Rain., Pcpn., Load~ Acceler.

2Y.:

C%' 109l_Co, ~ryC'

'Y

_Cet , 18°C mm mm mm kN/m 1110'2 1130'2 1I100~ Zone ation

kN/m kN/m kN/m Ratio, A

15

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14

DESIGN DATA FOR SELECTED LOCATIONS IN CANADA Design Temperature

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15

DESIGN DATA FOR SELECTED LOCATIONS IN CANADA Design Temperature

Province January July2V2% Degree 15 One Ann. Gnd.

Location ₂1_12%,_1%, Below Rain., Rain., Pcpn., _18·C _mm

~f~~

mm mm ·C ·C Cobourg ... -21 -23 30 23 4000 23 76 810 2.1 0.46 0.55 0.65 1 0.02 Cochrane ... -34 -36 29 21 6294 20 87 883 3.3 0.26 0.32 0.39 1 0.02 Colborne ... -21 -23 29 23 4100 23 76 810 2.1 0.44 0.52 0.62 1 0.02 Collingwood ... -22 -24 29 22 4195 28 128 786 3.8 0.25 0.34 0.45 1 0.02 Cornwall ... -23 -25 30 23 4419 28 71 897 2.5 0.30 0.37 0.46 2 0.04 Corunna ... -16 -18 31 23 3850 23 89 810 1.5 0.35 0.43 0.52 0.02 Deep River ... -29 -32 30 22 5100 23 89 740 2.6 0.20 0.24 0.28 0.04 Deseronto ... -22 -24 28 23 4030 23 89 840 2.1 0.32 0.39 0.48 0.02 Dorchester ... -18 -20 30 23 4030 28 89 910 1.9 0.33 0.43 0.55 0.02 Dorion ... -33 -35 28 21 5890 20 76 740 3.3 0.25 0.29 0.34 0.02 Dresden ... -16 -18 31 24 3670 28 76 790 1.5 0.32 0.39 0.48 1 0.02 Dryden ... -34 -36 27 22 6107 25 114 702 3.0 0.21 0.25 0.29 0 0 Dunbarton ... -19 -21 30 23 4030 23 102 810 2.1 0.43 0.52 0.64 1 0.02 Dunnville ... -15 -17 30 24 3852 23 102 890 1.8 0.33 0.39 0.45 2 0.04 Durham ... -20 -22 29 22 4593 28 86 1038 3.8 0.31 0.39 0.50 1 0.02 Dutton ... -16 -18 31 24 3750 28 89 890 1.6 0.34 0.43 0.53 1 0.02 Earlton ... ·33 ·36 30 21 5866 23 99 790 3.3 0.32 0.40 0.51 1 0.02 Edison ... -34 -36 28 22 6000 25 89 630 3.1 0.20 0.24 0.28 0 0 Elmvale ... ·24 ·26 29 22 4580 28 127 840 3.5 0.24 0.32 0.42 1 0.02 Embro ... ·18 ·20 29 23 4130 28 89 890 2.4 0.33 0.43 0.54 1 0.02 Englehart ... ·33 ·36 30 21 5850 23 87 871 3.3 0.29 0.37 0.47 1 0.02 Espanola ... -25 ·27 28 21 5070 23 89 810 3.0 0.28 0.37 0.48 1 0.02 Exeter ... ·17 ·19 30 23 4080 25 89 970 2.1 0.37 0.48 0.60 1 0.02 Fenelon Falls ... -25 ·27 30 23 4650 25 133 809 2.8 0.25 0.32 0.41 1 0.02 Fergus ... -20 ·22 29 23 4625 33 118 901 3.8 0.26 0.32 0.40 1 0.02 Fonthill ... -IS -17 30 23 3775 23 102 840 2.4 0.33 0.39 0.46 2 0.04 Forest. ... -16 -18 31 23 3844 23 87 910 1.8 0.39 0.48 0.58 1 0.Q2 Fort Erie ... -15 -17 30 24 3500 23 102 860 2.2 0.36 0.43 0.50 2 0.04 Fort Frances ... -33 -35 29 22 5615 25 114 710 2.R 0.21 0.25 0.29 0 0 Gananoque ... ·22 -24 28 23 4150 23 89 910 2.3 0.35 0.43 0.52 1 0.02 Georgetown ... -19 -21 30 23 4249 28 128 831 2.4 0.27 0.34 0.42 1 0.02 Geraldton ... -35 ·38 28 21 6310 20 65 718 3.5 0.20 0.24 0.28 0 0 Glencoe ... -16 -18 31 24 3882 28 66 845 1.6 0.31 0.39 0.49 1 0.02 Goderich ... -16 ·18 29 23 3692 23 84 922 2.5 0.40 0.50 0.62 1 0.02 Gore Bay ... -23 -25 29 21 4879 23 92 868 2.7 0.30 0.36 0.43 1 0.02 Graham ... -37 -40 29 22 6583 23 62 816 3.3 0.21 0.25 0.29 0 0 Gravenhurst.. ... -26 -28 29 22 4740 25 114 1020 3.1 0.19 0.25 0.33 1 0.02 Grimsby ... -16 -18 30 23 3577 23 123 861 1.7 0.36 0.43 0.50 2 0.04 Guelph ... -19 -21 29 23 4262 28 103 833 2.6 0.25 0.30 0.36 1 0.02 Guthrie ... -24 -26 29 22 4520 28 127 840 2.7 0.21 0.29 0.39 1 0.02 HagersviUe ... -16 -18 30 23 3999 25 83 842 1.7 0.33 0.39 0.46 0.02 Haileybury ... -32 -35 30 21 5379 23 65 799 3.2 0.32 0.39 0.49 0.02 Haliburton ... -27 -29 29 22 4969 25 103 928 3.5 0.19 0.25 0.31 0.02 Hamilton ... -17 -19 31 23 3952 23 117 814 1.6 0.36 0.43 0.50 0.04 Hanover ... -19 -21 30 22 4400 28 76 910 3.6 0.34 0.43 0.54 0.02 Hastings ... -23 -26 30 23 4400 28 89 790 2.7 0.29 0.37 0.47 1 0.02 Hawkesbury ... -25 -27 30 23 4800 23 89 876 3.0 0.31 0.37 0.45 2 0.04 Hearst ... -34 -36 28 21 6500 20 63 710 2.9 0.20 0.25 0.32 1 0.02 Honey Harbour ... -24 -26 29 22 4650 23 127 890 3.8 0.25 0.34 0.45 1 0.02 Hornepayne ... -37 -40 28 21 6614 20 83 736 2.7 0.19 0.25 0.31 0 0 Huntsville ... -26 ·29 29 22 4796 25 104 917 4.0 0.19 0.25 0.33 1 0.02 Ingerson ... -18 -20 30 23 4030 28 89 890 2.0 0.33 0.43 0.54 1 0.02 Jarvis ... -16 -18 30 23 3850 28 102 860 1.7 0.33 0.39 0.47 1 0.02 Jellicoe ... -36 -39 28 21 6250 20 76 710 3.5 0.21 0.25 0.29 0 0 Kapuskasing ... -33 -35 28 21 6365 20 80 833 2.9 0.23 0.28 0.34 1 0.02 Kempville ... 25 73 829 2.7 0.30 0.37 0.46 2 0.04 Kenora ... 25 128 647 3.1 0.20 0.24 0.28 0 0 Killaloe ... 23 62 669 2.8 0.24 0.29 0.36 1 0.02 Kincardine ... 76 890 3.7 0.40 0.50 0.62 1 0.02 Kingston 119 900 2.2 0.35 0.43 0.52 1 0.02 Column 1 8 9 10 11 12 13 14 15

NATIONAL BUILDING CODE THE SUPPLEMENT

Copyright

©

NRC

1941

- 2019

World

Rights

Reserved

©

CNRC

1941-2019

Droits

réservés

pour

tous

pays

THE SUPPLEMENT

to the

NATIONAL BUILDING CODE

of Canada

1980

ARCHIVES

Issued

by

the

Associate Committee on the National Building Code

National Research Council of Canada

Ottawa

Price

$7.30

NRCC No. 17724

Copyright

©

NRC

1941

- 2019

World

Rights

Reserved

©

CNRC

1941-2019

Droits

réservés

pour

tous

pays

THE SUPPLEMENT

to the

NATIONAL BUILDING CODE

of Canada

1980

Issued by the

Associate Committee on the National Building Code

National Research Council of Canada

Ottawa

NRCC No. 17724

Copyright

©

NRC

1941

- 2019

World

Rights

Reserved

©

CNRC

1941-2019

Droits

réservés

pour

tous

pays

Copyright

©

NRC

1941

- 2019

World