CLIMATIC INFORM
for
BUILDING DESIGN IN
:ATION
CANADA
SUPPLEMENT No.
1
TO THE NATIONAL BUILDING CODE
OF CANADA
Issued
by
the
Associate Committee on the National Building Code
National Research Council of Canada
Ottawa
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ASSOCIATE COMMIlTEE ON THE NATIONAL BUILDING CODE
C. D. Carruthers (Chairman) H. B. Dickens (Deputy Chairman)
V. S. Baker J. G. Burchill S. D. C. Chutter R. F. DeGrace P. Dobush C. G. E. Downing J. T. Gregg W. B. Guihan R. V. Hebert J. S. Hicks H. T. Jones Retired* J. D. Beaty (Deceased) R. A. Bird W. G. Connelly I. Coop R. M. Dillon J. Longworth A.
T. Mann
C. J: McConnell R. N. McManus A.T. Muir
F. X. Perreault G. B. Pope H. R. Stenson R. A. W. Switzer J. M. Verreault C. J. WardD. W. Boyd (Research Advisor
-
Meteorology)
R. S. Ferguson (Research Advisor) R.
H .
Dunn (Secretary)T. R. Durley (Deceased)
S. A. Gitterman A. Matthews K. R. Rybka D. H. WallerJ. M. Robertson (Secretary until
January, 1973)
*Committee term completed during preparation of 1975 Code
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I I I
I
I
CLIMATIC
INFORMATION
for
BUILDING
DESIGN IN CANADA
I
i
?
1975
SUPPLEMENT No. 1
TO THE NATIONAL BUILDING CODE
OF CANADA
Issued by the
Associate Committee on the National Building Code
National Research Council of Canada
Ottawa
NRC No.
13986
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First Edition 1953 Second Edition 1960
Third Edition 1965 Fourth Edition 1970
Fifth Edition 1975
@National Research Council of Canada 1975 World Rights Reserved
Printed in Canada
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TABLE OF
CONTENTS
Page
...
List of Charts
vii
Preface
...
ix
...
Abbreviations
xi
...
January Design Temperatures
1
...
July Design Temperatures
2
...
Heating Degree-Days
3
...
Rainfall Intensity
4
...
One-Day Rainfall
4
...
Annual Total Precipitation
4
Snow Loads
...
5
...
Wind Effects
6
Permafrost
...
8
Seismic Zones
...
9
References
...
9
...
Charts1 to12
11
Table of Design Data for Selected Locations
...
37
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vii
Chart 1.
Chart 2.
Chart
3.
Chart 4.
Chart 5.
Chart
6.
Chart
7.
Chart 8.
Chart
9.
Chart 10.
Chart 11.
Chart 12.
LIST
OF
CHARTS
Page
January Design Temperature. 2% Per Cent Basis. degrees F
...
12
January Design Temperature. 1 Per Cent Basis. degrees F
...
14
July Design Dry-Bulb Temperature. 2% Per Cent Basis.
degrees F
...
16
July Design Wet-Bulb Temperature. 2% Per Cent Basis.
degrees F
...
18
Annual Total Degree-Days Below 65OF
...
20
Fifteen-Minute Rainfall. 10-Year Return Period. inches
...
22
Maximum One-Day Rainfall. inches
...
24
Annual Total Precipitation. inches
...
26
Maximum Snow Load on the Ground. psf
...
28
Hourly Wind Mileage. Annual Probability 1
/30.
miles per hour
...
30
Permafrost Region
...
32
Seismic Zones with Boundary Accelerations
...
34
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PREFACE
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 Supplement are, firstly, by means of maps, to indicate the variability and general distribution of those climatic ele- ments (including earthquake intensity a n d permafrost) that are most frequently considered in building design, secondly, to explain briefly how the design weather values are computed and thirdly 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 variation in different localities of Canada and that the Code can be applied nationally. 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 Secretary, Associate Committee on the National Building Code, National Research Council of Canada, Ottawa, Ontario, K 1 A OR6.
Information on seismic zones for municipalities not listed may be obtained by writing to the Seismology Division, Earth Physics Branch, Department of Energy, Mines and Resources, Ottawa K I A OE4.
The material in this Supplement is based on information supplied by the Atmospheric Environ- ment Service, Department of the Environment (formerly the Meteorological Branch, Department of Transport) and organized for the Associate Committee on the National Building Code by D.W. Boyd, Department of the Environment Meteorologist with the Division of Building Research, National Research Council of Canada.
Le Code national du bbtiment, ses supplements et les documents qui s'y rattachent sont disponi- bles en fran~ais. O n peut se les procurer en s'adressant au Secretaire, Comiti associe du Code national du bbtiment, Conseil national de recherches d u Canada, Ottawa, Ontario K1A OR6.
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ABBREVIATIONS
Abbreviations of words and phrases in this Supplement have the following meanings: ACNBC
. . .
Associate Committee on the National Building Codeann.
. . .
annual. . .
"
F degree(s) Fahrenheit. . .
fps feet per second
. . .
gnd. ground
hr
. . .
hour(s)in.
. . .
inch(es)min.
. . .
minute(s)mph
. . .
miles per hourN BC
. . .
National Building Code of Canadapsf
. . .
pound(s) per square foot pcpn.. . .
precipitation sta.. . .
station. . .
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CLIMATIC INFORMATION
for
BUILDING DESIGN IN CANADA
The choice of climatic elements that are included in this Supplement and the form in which they are expressed has been dictated largely by the requirement for specific values in several sections of the National Building Code of Canada. A few additional charts are 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. T o select design values for other locations in Canada, the observed or computed values of each element for specific observation stations were plotted on_ maps to the scale of 1 in. to 100 miles or 1 in 5,000,- 000. Isolines were drawn on these working charts to show the distributions of the design values. The charts in this handbook have been reduced from the working charts, but these small copies are not intended as a source of 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 included 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, these were also added to the list. In some cases the values obtained from the large-scale charts have not been rounded off for reasons explained later.
Neither the charts nor the list of design values should be expected to give a complete picture of the variations of these climatic elements. If application is made to the Secretary as mentioned above, values will be estimated for any location not included in the Table using the list of observed or computed values for weather stations, the large-scale manuscript charts and any more recent information that is available. In the absence of weather observations at any particular loca- tion, a knowledge of the local topography may be important. For example, cold air has a tendency to collect in depressions, precipitation 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.
All the weather records that were used in preparing the charts were, of necessity, observed at inhabited locations, and hence the charts apply only to populated areas, This is particularly significant in mountainous areas where the lines on the charts apply only to the populated valleys and not to the mountain slopes and high passes, where, in some cases, very different conditions are known to exist.
JANUARY DESIGN TEMPERATURES (CHARTS 1 AND 2)
A building and its heating system should be designed to maintain the inside temperature at some pre-det,ermined 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 occa- sionally 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 methods 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.
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The choice of a method to determine the winter design temperature depends to some extent on the form of the available temperature records. In Canada hourly temperatures in degrees Fahren- heit for 10 successive years were available on punched cards for over 100 stations, and from these cards it was possible to obtain frequency distributions. The winter design temperature is defined, therefore, as the lowest temperature at or below which only a certain small percentage of the hourly outside air temperatures in January occur. The Meteorological Branch, Department of Transport, prepared tabulations showing the number of hours in January in the 10 years from 195 1 to 1960 inclusive in which the temperature fell in each of over 50 two-degree intervals. From this it was possible to select the 2-degree interval below which only a small number of tempera- tures fell. T o find the required temperature to the nearest degree, an interpolation rule was devised based on the normal distribution. Using this rule, it was possible to select the temperature below which 1 per cent or 2% per cent of the January temperatures fell.
Tabulations and January design temperatures for 1 18 stations were obtained. The temperatures were plotted on maps and used to estimate design temperatures for the other stations in the Table. Since the pattern of January design temperature charts is similar to that of mean annual minimum temperature charts, the latter chart in the Atlas of Canada") influenced the pattern of these Janu- ary design temperature charts in the Far North where hourly temperature observations are scarce.
A more recent tabulation of hourly temperature distributions for all months for the 10-year period 1957 to 1966 has been published for 88 weather station^.'^) The earlier tabulation for 30 more stations is still the best basis for a consistent set of design temperatures, but the more recent tabulation could provide design temperatures for other months besides January.
In most cases the temperatures observed at airports have had to be used, and no adjustments have been made to allow for the city effect. The January winter design temperatures are not relia- ble to within 1 degree, but the differences between the 1 and 2% per cent values (which average about 4 degrees) are more reliable. The design temperatures, therefore, are listed to the nearest degree as an indication of these differences.
The 2% percent January design temperature is the value ordinarily used in the design of heating systems. In special cases when the control of inside temperature is more critical, the 1 per cent value may be used.
JULY DESIGN TEMPERATURES (CHARTS 3 AND 4)
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 satisfactorily. Failure to maintain the inside temperature and humidity at the pre-determined levels will usually 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.
The summer design temperatures in this supplement are based on an analysis of July air temper- atures 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 B~ughner.'~) If the summer dry-bulb and wet-bulb design temperatures are defined a s the tempera- tures that are exceeded 2% per cent of the hours in July, then design values can be obtained directly for these 33 stations.
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extent on ; Fahren- .om these ; defined, ge of the -tment of :ars from 31s. From tempera- .s devised Ire below peratures he Table. ninimum ese Janu- e scarce. e 10-year >n for 30 )re recent justments not relia- 1 average e nearest )f heating per cent the inside know the ifactorily
.
11 usually ion is not in many )t greatly r temper-=
of most rature. It generally .ore com- and wet- for each ~tions by tempera- obtainedAs mentioned above, the pattern of January design temperature is similar to that for the mean annual minimum. In the same way, the pattern of July design temperature is much like that of the mean annual maximum. C r o d 4 ) used these similarities as a basis for computing design tempera- tures for places in the U.S.A. for which only daily maximum and minimum temperatures were observed. The July dry-bulb design temperatures for the 33 Canadian stations were subtracted from the mean annual maximum temperatures for the same period of years and the differences plotted on a map. The differences are all between 3 and 11 degrees. With this small range, the 33 stations seem to be enough to establish differences, within an accuracy of about 1 degree, for any location. Mean annual maxima based on the period 1921 to 1950 were available for about 170 locations. For these, the differences were read or estimated from the map and July dry-bulb design temperatures obtained. These 170 stations were used to prepare Chart 3 from which values were estimated for about 450 additional locations. A more recent tabulation of hourly temperature dis- tributions for all months for the 10-year period 1957 to 1966 has been published for 88 weather
station^.'^) The 170 stations used for Chart 3 are probably still the best basis for a consistent set of
design temperatures, but the more recent tabulations could provide design temperatures for other months besides July.
The July wet-bulb design temperatures for the 33 stations were plotted directly on a map. The range from 62 to 75 (excluding Yukon and NWT) is a little more than for the dry-bulb differences, but is still small enough to yield reasonably accurate wet-bulb design temperatures. The northern part of the chart was not drawn in because data are very sparse and because cooling and dehumi- difying are seldom needed in that area. July 29'2 per cent wet-bulb design temperature values were read from the map for all locations with dry-bulb design values of 75°F or higher.
In many cases the temperatures observed at airports have had to be used and no adjustments have been made to allow for the city effect.
The summer design temperatures are not reliable to within 1 degree, although they have been estimated and tabulated to the nearest degree.
HEATING DEGREE-DAYS (CHART 5)
It has long been known that the amount of fuel or energy required to keep the interior of a small building at about 70°F when the outside air temperature is below 65°F is roughly proportional to the difference between 65°F and the outside temperature. Wind speed, solar radiation and the extent to which a building is exposed to these elements also affect the heat required, but there is no convenient way of combining these effects. For average wind and radiation conditions, however, the proportionality with the temperature difference still holds and hence the heating degree-days are based on temperature alone.
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 65°F and the mean temperatures for every day in the year when the mean temperature is below 65°F. It is assumed that no heat is required when the mean outside air temperature for the day is 65°F or higher.
Daily degree-days have been computed for many years at Victoria, Winnipeg, Toronto and Halifax. The values given in the Table for these 4 cities are the average annual totals for the 30- year period from 193 1 to 1960.
Daily degree-days were not available for the full 30-year period for other stations. An approxi- mate but reasonably accurate method of obtaining heating degree-days from monthly mean temp- eratures was devised by Thorn.'') This method was used to compute normal monthly and annual degree-day totals for over 600 stations based on the period 1931 to 1960.(6) The annual totals were plotted on a map (Chart 5) and used to estimate values for locations without weather stations. Computed values are shown in the Table to the nearest unit as computed but should not be relied on to within less than 100 to 150 degree-days. Values read from the manuscript chart are to the nearest 100 degree-days.
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RAINFALL INTENSITY (CHART 6)
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 fac- tors included in the tables in the ACNBC Canadian Plumbing Code will probably reduce the fre- quency to a reasonable value and, in addition, the occasional failure of a roof drainage system will not be particularly serious in most cases.
Chart 6 is a revision of the corresponding chart by Bruce'') which shows the 15-min. rainfall, in inches, that will probably be exceeded on the average once in 10 years. In 1968 there were 58 recording rain gauge stations with 5 or more years of record available to Bruce. There are now 139 stations with 7 or more years of record.
It is very difficult to estimate the pattern of rainfall intensity in British Columbia where precipi- tation is extremely variable. Lines have been drawn on the map, however, to indicate the probable intensity in valley bottoms or extensive level areas. Much greater intensities may occur on moun- tain sides.
ONE-DAY RAINFALL (CHART 7)
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. Although 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 pub- lished by the Meteorological B r a n ~ h . ' ~ ) Since these values are all for predetermined 24-hr periods, beginning and ending at the same time each morning, it is probable that most of them have been exceeded in periods of 24-hr including parts of 2 consecutive days. The maximum "24-hr" rainfall (i.e. any 24-hr period) according to Hershfield and Wilson is, on the average, about 11 3 per cent of the maximum " 1 -day7' rainfall.(9)
Most of the rainfall amounts that were used in preparing Chart 7 were based on reports cover- ing between 20 and 30 years. These maximum values differ greatly within relatively small areas where little difference would be expected. The variable length of records may account for part of this variability which might be reduced by a n analysis of annual maxima instead of merely select- ing the maximum in the period of record. Whatever the reason, the variability has necessitated a considerable amount of smoothing in drawing the chart, and hence the isolines d o not in all cases agree with the observed maximum 1-day rainfalls. The tabulated values are intended to be repre- sentative of the immediate area, and therefore include some local variations which cannot be shown on the small-scale chart.
ANNUAL TOTAL PRECIPITATION (CHART 8)
The total amount of precipitation that normally falls in 1 year is frequently used as a general indication of the wetness of a climate. A; such it is thought to have a place in this Supplement. Total precipitation is the sum in inches of the measured depth of rainwater and 1/10 of the meas- ured depth of snow (since the average density of fresh snow is about 1/10 that of water).
The average annual total precipitations for the 30-year period from 1921 to 1950 were used in preparing Chart 8. The values were selected from a list of precipitation normals prepared by the
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nfall that down the the most le flow of :h can be eeded on min. and afety fac- :e the fre- /stem will ainfall, in : were 58 : now 139 e precipi- probable 3n moun- rainwater the roof. n practice maximum and pub- ,r periods, have been r" rainfall her cent of ~ r t s cover- nall areas 'or part of ely select- :ssitated a n all cases I be repre- cannot be a general .pplemen t. the meas- :re used in red by the
Meteorological Branch.(Io) All stations with records for the full 30 years were plotted on the map or compared with nearby stations that had already been plotted to ensure consistency. Many adjusted values were used in areas where unadjusted 30-year values were not available. The corre- sponding chart in the Atlas of Canada") was used for reference.
SNOW LOADS (CHART 9)
The roof of a building should be able to support the greatest weight of snow that is likely to accumulate on it. Some observations of snow loads on roofs have been made in recent years, but they are not sufficiently numerous to form the basis for a snow load chart. Similarly, observations of the weight or water equivalent of the snow on the ground are not sufficient for such a chart. Although the roof load and water equivalent observations are necessary, as mentioned below, the chart must be based on the more numerous observations of the depth of snow on the ground.
The estimation of the design snow load on a roof from snow depth observations involves the fol- lowing 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 absorbed
by the snow.
4. Because the accumulation of snow on roofs is often different from that on the ground, cer- tain 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 10 to 18 years were available for over 200 stations. These data were assembled and analysed using Gumbel's extreme value method as explained by Boyd."') The resulting chart showed the distribution in Canada of the snow depth which will probably be equalled or exceeded, on the average once in 30 years, or which has 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 usually assumed in Canada that 0.1 is the average specific gravity of new snow. The 30-year maximum snow depth will almost certainly occur immediately after a n unusually heavy snowfall, and hence a large proportion of the snow cover will have a low density. I t therefore seemed reasonable to assume a mean specific gravity under these unusual circumstances of about 0.2 for the whole snow cover. In practice it is convenient to assume that 1 inch of snow cover corresponds to a load of exactly 1 psf. This corresponds to a specific gravity of 0.192, the value which was used in preparing the Chart.
Because the heaviest loads in Canada frequently occur when early spring rain adds to an already heavy snow load, it was considered advisable to increase the snow load by the load of rainwater 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.' I )
The results from several winters of a survey 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 Sec- tion 4.1 of the National Building Code 1975. The Code also permits further decreases in design snow loads for steeply sloping roofs, but requires substantial increases for roofs where snow accu- mulation may be more rapid. Recommended adjustments are given in NBC Supplement No. 4, "Commentaries on Part 4 of the National Building Code of Canada 1975."
Chart 7 shows the general distribution of snow loads on the ground, that is, the load due to snow which will bz exceeded on the average once in 30 years, plus the load due to the maximum 1- day rainfall in the late winter or early spring. Values of the snow loads on the ground were read from the large-scale original of Chart 7 and are listed in the Table. The snow loads are tabulated in whole pounds per square foot but are not reliable to this accuracy.
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Charts on such a small scale as those in this Supplement cannot show local differences in the weather elements, even where these are known to exist. All the weather observations used in pre- paring Chart 7 were, of necessity, taken at inhabited locations, and hence the charts apply only to permanently populated areas. This is particularly significant in mountainous areas where the lines on the chart apply only to the populated valleys and not to the mountain slopes, where, in some cases, much greater snow depths are known to accumulate and must be taken into account in the design of roofs.
After the chart was drawn several detailed studies of relatively small areas were carried out and some adjustments made in the Table.
WIND EFFECTS (CHART 10)
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 Canada.
The provision of "velocity pressures" for both average wind speeds and gust speeds for estimat- ing 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 pressures" 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 National Building Code of Canada 1975 and in Supplement No. 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 a n 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, how- ever, 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 analysed using Gumbel's extreme value method to estimate the hourly mileages that would have one chance in 10,30 and 100 of being exceeded in any 1 year. The " 1 in 30" hourly mileages were used to pre- pare Chart 10.
Values of the "1 in 30" hourly mileages for the additional 500 locations in the Table could have been estimated from the large-scale original of Chart 10. However, to ensure consistency with the wind gust speeds published in earlier editions of this supplement, it was necessary to compute hourly mileages from the published gusts using the equation:
V = (G-5.8)/ 1.29
where V is the hourly mileage and G is the gust speed in miles per hour. This equation was based on a comparison of over 1500 hourly mileages of 30 miles or over (as recorded by cup anemome- ters) with the corresponding maximum gust speeds (as recorded by Dines pressure tube anemometers).
Values of the hourly mileages for annual probabilities of 1/10 and 1/100 were readily computed for the 100 stations in the original Gumbel analysis. For the other 500 locations it was necessary to estimate the value of the parameter I/& which is a measure of the dispersion of the individual annual maximum hourly mileages. T o d o this the 100 known values were plotted on a large scale map from which estimates were made for the other locations. Knowing the "1 in 30" hourly mile- ages and the values of I/&, the "1 in 10" and "1 in 100" values could be computed.
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:es in the :d in pre- y only to the lines , in some ~ n t in the 1 out and strongest ; the only :signed to linutes to linutes or Canada. r estimat- nd speeds s" for the 5pe of the : National d in more itations in ur, or the lind speed sent, how- 'he annual : analysed ~ n e chance jed to pre- :ould have :y with the compute
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 pres- sure, 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 pressu;e, P, in paunds pe;square foot is given by the equation
P =
cv2
where C depends on air temperature and atmospheric pressure as explained in detail by Boyd.('2) 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 pressures cor- responding to the hourly mileages with annual probabilities of being exceeded of 1/10, 1/30 and 1/ 100. The pressures are shown in the Table in columns headed only by the numerical values of these probabilities.
In the 1975 edition of the National Building Code the design gust pressures for structural ele- ments are twice the hourly mileage pressures. Because wind speeds are squared to get pressures, the above statement is equivalent to saying that the gust factor is the square root of 2. The table below shows that the 1975 requirements increase the wind loads by less than 8 per cent over those of 1965 computed from gusts given by the equation
G = 5.8
+
1.29VFor buildings over 40 ft high, the gust velocity pressures and suctions must be increased according to a table in Section 4.1 of the National Building Code 1975 which is based on the assumption that the gust speed increases in proportion to the 1/10 power of the height. The average
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 Supplement No. 4.
The calculations for building vibrations in Supplement No. 4 have been drawn up for wind speeds measured in feet per second. The table below may be used for converting the wind pres- sures in the main Table to wind speeds in feet per second. It is based on the equation
P = .0027 (3600/5280)2v2 was based anemome- ;sure tube computed ecessary to individual large scale ourly mile-
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PERMAFROST (CHART 11)
The lines on Chart 1 1 indicate the approximate southern limit of permafrost and the boundary between the discontinuous and continuous permafrost zones in Canada. The distribution of per- mafrost varies from continuous in the north to discontinuous in the south. In the continuous zone permafrost occurs everywhere under the ground surface and is generally hundreds of feet thick. Southward, the continuous zone gives way gradually to the discontinuous zone where permafrost exists in combination with some areas of unfrozen material. The discontinuous zone is one of broad transition between continuous permafrost and ground having no permafrost. In this zone, permafrost may vary from. a widespread distribution with isolated patches of unfrozen ground to predominantly thawed material containing islands of ground that remain frozen. I n the southern area of this discontinuous zone, permafrost occurs as scattered patches and is only a few feet thick.
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boundary on of per- uous zone feet thick. ~ermafrost is one of this zone, ground to t southern a few feet
It is emphasized that the lines on this map must be considered as the approximate location of broad transition bands many miles wide. Permafrost also exists at high altitudes in the mountains of Western Canada a great distance south of the southern limit shown on the map. Information on the occurrence and distribution of permafrost in Canada has been compiled by the Division of Building Research, National Research Council.(13. 14)
SEISMIC ZONES (CHART 12)
The parameter used as the basis for establishing the seismic zones is A,, defined as the ground acceleration with an annual probability of being equalled or exceeded of 1 in lOO.(I5) This map is based on the statistical computer analysis of past earthquakes throughout the country for this century.(I7) It is corroborated by the results from a larger but less reliable seismic sample dating back to 1638.(16) The map reflects the opinion of experts in the fields of seismology, geology and engineering from industry, government and universities comprising members of the Canadian National 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 for each zone, as a fraction of gravitational acceleration, are shown in the table on Chart 12. The zone boundaries in terms of A,, are shown in Table 5-2 of the Commentary on Effects of Earthquakes.(")
In the Arctic Region and other parts of the Northwest Territories, there are insufficient data for a statistical study. The zone boundaries have been drawn by the Seismologists of the Department of Energy, Mines and Resources from their knowledge of earthquake activity in these areas.
REFERENCES
(1) "Atlas of Canada," Dept. of Mines and Technical Surveys, Geographical Branch, Ottawa 1957.
(2) "Hourly Data Summaries." Dept. of Transport, Meteorological Branch, various dates from May 1967 to December 1968.
(3) Boughner, C.C. "Percentage Frequency of Dry- and Wet-bulb Temperatures from June to September at Selected Canadian Cities." Dept. of Transport, Canadian Meteorological Memoirs, No. 5, Toronto, 1960.
(4) Crow, L.W. "Study of Weather Design Conditions for American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc." Research Project No. 23, January 31, 1963.
( 5 ) Thom, H.C.S. "The Rational Relationship between Heating Degree-Days and Tempera-
ture." Monthly Weather Review. Vol. 82, No. 1, p. 1-6, Jan. 1954.
(6) "Heating Degree-Day Normals below 65°F-Based on the Period 1931-1960." Dept. of 'Transport, Meteorological Branch, Climate Data Sheets No. 5-64, October 30, 1964.
(7) Bruce, J.P. "Rainfall Intensity, Duration, Frequency Atlas for Canada." Dept. of Trans-
port, Meteorological Branch, Climatological Studies Number 8, Toronto, 1968.
(8) "Maximum Precipitation Reported on any One Observation Day 1931-1958." Dept. of
Transport, Meteorological Branch, Climatic Data Sheets No. 9-59, Oct. 1959.
(9) Hershfield, D.M. and Wilson, W.T. "Generalizing of Rainfall - Intensity - Frequency
Data." International Association of Scientific Hydrology, General Assembly, Toronto, 1957, Vol. 1. p. 499-506.
(10) "Temperature and Precipitation Normals for Canadian Weather Stations Based on the Period 1921-1950." Dept. of Transport, Meteorological Branch, CIR-3208, CLI-19, June 1959.
(11) Boyd, D.W. "Maximum Snow Depths and Snow Loads on Roofs in Canada." Proceed- ings, 29th Annual Meeting, Western Snow Conference, Spokane, Wash., April 1961.
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(12) Boyd, D.W. "Variations in Air Density over Canada." National Research Council, Divi- sion of Building Research, Technical Note No. 486, June 1967.
(13) "Permafrost Map of Canada" (a joint production of the Geological Survey of Canada and DBR/NRC). August 1967 - NRC 9769.
(14) Brown, R.J.E. "Permafrost Map of Canada." Reprint from Canadian Geographical Jour- nal, February 1968, pp. 56-63 - NRC 10326.
(15) "Commentary on Effects of Earthquakes," Supplement No. 4 to the National Building Code 1975.
(16) Milne, W.G. and Davenport, A.G. "Distribution of Earthquake Risk in Canada," Bulle- tin 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.
(17) Whitham, K., Milne, W.G. and Smith, W.E.T. "The New Seismic Zoning Map for Can- ada, 1970 Edition," The Canadian Underwriter, June 1970.
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:il, Divi- Canada :a1 Jour- Building ," Bulle- Fourth Tor Can-
CHARTS 1 to 12
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JANUARY DESIGN TEMPERATU
2 % PER CENT BASIS
DEGREES F
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DESIGN DATA FOR SELECTED LOCATIONS IN CANADA
Design Temperature Hourly Wind
Degree 15 One Ann . Gnd .
Province January July 2%% Days Min . Pressures Day Tot . Snow
and Below Rain, Rain. Pcpn.. Load. Seismic Zone Location 2%%. 1%
.
Dry. Wet. 65OF in . in . in . psf 0 1/30. 1/100.OF "F OF OF psf psf psf hitish Columbia ... Abbotsford 13 1 1 84 68 5735 0.4 4.0 60 50 8.7 1 1.5 16.9 3 ... Agassiz 7 4 87 69 5464 0.3 4.5 60 60 11.5 15.6 20.8 2 ... Alberni 22 20 87 65 5865 0.4 4.5 67 52 9.8 12.1 14.7 3 ... . Ashcroft -14 19 95 69 7452 0.4 2.0 9 27 5.9 7.3 9.0 1 ... Beatton River -36 -40 78 64 1283 1 0.5 2.0 17 60 4.6 5.7 7.0 1 ... Burns Lake -24 -29 8 1 64 10500 0.4 2.0 17 40 6.4 7.6 9.0 2 ... Cache Creek -14 - 19 95 69 7500 0.4 2.5 10 30 5.9 7.3 8.9 1 ... Campbell River 18 15 79 64 5900 0.4 4.5 55 58 9.5 12.1 15.1 3 ... Carmi -11 -16 91 69 9565 0.4 2.0 21 80 5.1 6.9 9.1 I . ... Castlegar -2 -8 89 68 8000 0.4 2.0 28 65 4.7 6.2 8.1 0 ... Chetwynd -33 -38 81 64 10800 0.6 2.5 16 50 6.7 7.9 9.2 1 ... Chilliwack 10 7 86 68 5496 0.3 4.5 59 55 9.9 13.2 17.2 2 ... Cloverdale 17 14 84 67 5600 0.3 4.0 50 40 9.3 12.1 15.1 3 ... Comox 18 15 80 64 5980 0.4 4.0 53 57 9.3 12.1 15.4 3 ... Courtenay 18 15 81 64 6000 0.4 4.0 53 57 9.3 12.1 15.4 3 ... Cranbrook -17 -22 89 66 8743 0.4 2.5 15 44 4.7 6.1 7.8 0 ... Crescent Valley -5 - 1 1 88 67 7946 0.4 2.0 29 67 4.7 6.1 7.8 0 ... Crofton 21 19 81 64 5800 0.3 4.0 38 35 10.1 12.1 14.3 3 ... DawsonCreek -35 -40 81 64 10800 0.7 2.5 15 49 6.5 7.8 9.2 1 ... DogCreek -20 -24 87 68 9383 0.4 2.0 15 37 6.5 7.8 9.2 1 ... Duncan 21 19 85 64 5900 0.3 4.0 32 35 10.1 12.1 14.3 3 Elk0 ... -20 -24 85 66 9000 0.5 3.5 20 50 5.6 7.8 10.4 0 Fernie ... -2 1 -25 84 66 9144 0.5 4.0 41 80 6.8 8.9 11.5 0 ... FortNelson -41 -44 84 64 12777 0.5 2.5 16 44 4.0 5.0 6.2 1 ... FortSt.John -34 -39 80 64 10874 0.6 2.5 I5 53 6.4 7.5 8.8 1 Glacier ... -17 -22 81 64 10504 0.4 3.5 52 161 5.0 6.1 7.3 1 Golden ... - 19 -23 86 64 9093 0.3 2.5 18 75 5.6 6.7 8.0 0 Gr-adForks ... -4 -9 95 69 7431 0.4 1.5 17 40 5.5 7.6 10.1 1 Greenwood ... -5 - 10 94 69 8304 0.4 1.5 17 40 6.0 8.2 10.8 1 Haney ... 15 12 85 67 6055 0.4 4.5 65 45 9.8 12.6 16.1 3 Hope ... 2 -3 89 69 5808 0.3 4.0 62 70 8.5 1 1.5 15.2 2 ... Kamloops -10 -16 94 69 6799 0.5 2.0 10 35 6.4 7.8 9.4 1 Kaslo ... -9 -15 84 66 7553 0.4 2.0 30 50 4.7 6.0 7.5 0 Kclowna ... 0 -5 91 69 6776 0.4 2.0 12 41 7.1 8.9 11.1 1 kimberley ... -16 -21 88 66 8965 0.4 2.0 15 55 4.7 6.1 7.8 0 Kitima~Plant ... 2 -1 76 62 7562 0.5 5.5 97 70 7.9 9.4 11.2 3 KitimatTownsite ... 2 -1 76 62 7600 0.5 6.0 88 90 7.9 9.4 11.2 3 Langley ... 17 14 84 67 5500 0.3 4.5 60 44 9.5 12.1 15.2 3 Lillooet ... -10 -15 93 69 7600 0.4 2.0 14 50 6.6 8.2 10.1 1 Lytton ... i3 -8 95 69 5934 0.4 2.5 17 60 6.5 8.2 10.3 1 Mackenzie ... -33 -38 80 64 10900 0.4 2.5 17 55 5.1 6.1 7.3 1 McBride ... -3 1 -36 88 66 10500 0.5 2.0 21 60 5.7 6.8 8.0 1 McLeod Lake ... -32 -37 81 64 I0500 0.4 2.5 18 55 5.1 6.1 7.3 1 Massel ... 18 15 66 - 6839 0.5 3.0 56 30 10.2 12.1 14.3 3 Merrit~ ... -15 -21 93 69 7700 0.3 2.5 9 50 6.6 8.2 10.1 I Missioncity ... 14 1 1 85 68 5500 0.5 5.0 70 50 9.7 12.6 16.2 3 Montrose ... 0 -6 90 68 7500 0.4 2.0 25 65 4.5 6.2 8.4 0 Nakusp ... - 1 1 -15 89 67 7600 0.4 2.0 31 80 4.9 6.2 7.8 0 Nanaimo ... 20 17 78 64 5554 0.3 3.0 37 46 9.8 12.1 14.8 3 ... Nelson -5 - 1 1 88 67 7200 0.4 2.5 29 65 4.7 6.1 7.8 0 New Westminster ... 19 15 84 66 5412 0.4 4.5 55 40 9.2 11.5 14.2 3 NorthVancouver ... 19 15 78 66 5700 0.4 5.0 70 40 9.2 11.5 14.2 3 OceanFalls ... 9 5 76 62 6472 0.5 9.2 177 60 9.7 11.5 13.6 3 100 Mile House ... -20 -24 89 68 9000 0.4 2.0 18 55 6.4 7.6 9.0 1 Osoyoos ... 3 -2 91 69 6500 0.4 2.0 1 1 30 6.3 8.9 12.3 1 Penticton ... 3 - 1 91 69 6522 0.4 2.0 12 27 8.3 11.0 14.2 1 PortAlberni ... 22 20 87 65 5865 0.4 4.5 67 52 9.8 12.1 14.7 3 PortHardy ... 21 19 70 61 6730 0.5 60 53 10.1 12.1 14.3 3 ... Port McNeill 2 1 19 73 62 6400 0.5 50 52 10.1 12.1 14.3 3
,
Powell River ... I5 I? 79 64 5362 0.3 35 65 8.8 11.5 14.8 3Copyright
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DESIGN DATA FOR SELECTED LOCATIONS IN CANADA
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DESIGN DATA FOR SELECTED LOCATIONS IN CANADA ' 9 I : 3 5 7 ? 3 5 3 5 9 5 6 7 4 0 4 0 3 0 0 2 2 9 5 7 5 4 2 6 9 0 . 8 0 . 4 I . 2 . 4 . 0 . 2 . 7 Province and Seismic Zone I 1 3 1 3 I 1 2 1 3 I 3 3 2 2 3 3 I 1 2 1 3 0 1 3 1 3 1 1 3 I 3 0 0 I 0 0 0 0 I 0 I 0 0 0 0 0 0 0 I 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Location
I:
. 5 0 . 4 0 . 3 0 ... Pincher CreekI
... Ranfurly Red Deer ...Rocky Mountain House ... ... Slave Lake Stettler ... ... Stony Plain Suffield ... Taber ... ... Turner Valley Valleyview ... ... Vegreville Vermilion ... Wagner ... Wainwright ... ... Wetaskiwin ... Whitecourt ... Wimborne Saskatchewan Assiniboia ... Battrum ... Biggar ... ... Broadview Dafoe ... Dundurn ... Estevan ... ... Hudson Bay ... Humboldt ... Island Falls Kamsack ... ... Kindersley ... Lloydminster ... Maple Creek ... Meadow Lake Melfort ... Melville ... Moose Jaw ... ... Nipawin North Battleford ... ... Prince Albert Qu'Appelle ... Regina ... F.osetown ... Scott ... ... Strasbourg Swift Current ... Uranium City ... ... Weyburn Yorkton ... Manitoba Beausejour ... ... Boissevain Brandon ... Churchill ... Dauphin ... ... Flin Flon Gimli ... ... Island Lake Below
*I
;:5: 15 Min . Rain. in . Gnd . Snow Load. PS f 37 3 1 30 4 1 42 25 35 22 22 3 5 44 3 1 28 43 26 28 48 27 24 30 36 4 1 33 35 43 50 35 36 50 35 3 1 32 42 38 47 28 43 39 44 4 1 35 35 35 35 4 1 24 3 7 35 One Day Rain. in . Hourly Wind Pressures Ann . Tot . Pcpn., in . 3.5 21 3.5 17 4.5 16 4.0 23 3.0 18 3.0 16 4.0 20 2.5 13 3.0 15 4.0 23 2.0 18 3.5 17 3.0 17 2.5 17 2.5 15 3.0 17 2.5 21 3.5 17 3.0 14 2.5 14 4.0 14 3.5 17 3.0 16 3.0 14 3.0 17 2.5 16 2.5 15 2.5 19 3.0 16 3.0 13 2.5 15 3.0 14 2.5 15 3.0 16 3.5 16 2.5 15 3.0 16 3.0 13 3.0 16 2.5 17 3.0 15 3.0 13 3.0 14 3.0 14 3.5 15 2.5 15 2.0 13 3.0 16 3.5 17 3.5 20 4.0 19 4.0 19 3.5 14 3.5 18 3.0 17 4.5 19 2.5 20 0 psf / 100. PS f Seismic Zone 14.7 18.3 4.9 6.1 6.5 7.8 5.5 6.7 5.8 7.1 5.0 6.7 6.7 8.5 9.0 11.0 12.0 14.4 10.7 12.6 7.4 8.9 5.3 6.7 4.8 5.9 5.8 7.1 5.1 6.7 5.0 6.7 6.7 8.2 6.4 7.8 9.2 l 1.0 10.2 12.6 9.9 12.6 5.8 6.7 5.9 7.1 8.2 9.9 8.8 10.7 5.8 7.1 6.1 7.5 9.4 11.8 6.6 7.8 9.4 12.1 6.2 7.8 9.8 12.1 7.6 9.4 5.4 6.7 6.7 7.8 7.5 8.9 5.6 7.1 9.4 12.9 5.5 7.1 7.1 8.2 7.1 8.2 9.8 12.1 7.5 9.2 9.1 12.1 7.0 8.2 9.5 11.8 7.8 9.4 8.0 9.4 6.6 7.8 6.4 7.8 9.1 11.0 7.8 9.4 10.0 12.3 6.6 7.8 8.7 11.0 6.3 7.8 7.6 8.9 1 /30. psf 22.6 0 7.5 0 9.3 0 8.1 0 8.6 0 8.8 0 10.6 0 13.3 0 17.2 0 14.9 0 10.8 0 8.4 0 7.2 0 8.6 0 8.6 0 8.7 0 10.1 0 9.4 0 13.1 0 15.5 0 15.9 0 7.7 0 8.6 0 11.9 0 13.0 0 8.6 0 9.2 0 14.6 0 9.1 0 15.2 0 9.7 0 14.7 0 11.6 0 8.3 0 9.1 0 10.6 0 8.9 0 17.3 0 1Copyright
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DESIGN DATA FOR SELECTED LOCATIONS IN CANADA Degree Days Below 65°F 10900 14300 I0068 10899 11000 10800 10884 10700 10700 10800 10800 14400 10700 11500 12281 13900 10700 10800 10900 10679 7300 7500 8400 8300 8700 11400 12458 8800 11066 7900 9100 8200 7800 8400 7709 7300 7600 8800 8100 772 1 7202 7800 7900 7800 9300 6800 7200 7600 8100 8200 8400 8600 8200 7243 10900 6503 9700 7800 7600 8700 15 Min . Rain, in . 1 .I 0.3 . 1 1 1.3 1.0 1.4 1.3 1.1 1.1 . 1 1 1.1 0.4 1.1 0.8 0.6 0.4 1.1 1.3 . 1 1 1.1 1.0 0.9 . 1 1 . 1 1 1.0 0.8 0.9 0.9 1.0 1.1 1.0 1 . 1 0.9 1.1 0.9 1.0 0.9 1.0 1 . 1 1 . 1 0.9 0.9 1.0 0.9 1.0 0.9 0.9 1.0 1 . 0 1.1 1.1 1.0 1.1 1.0 0.9 1.1 1.0 1 . 1 0.9 1 . 0 Province and Location ... Lac du Bonnet ... LynnLake ... Morden ... Neepawa ... PineFalls ... Portage la Prairie ... Rivers . ... St Boniface ... St.Vita1 ... Sandilands ... Selkirk ... SplitLake ... Steinbach ... Swan River ... ThePas ... Thompson ... Transcona ... Virden ... Whiteshell ... Winnipeg Ontario ... AilsaCraig ... Ajax ... Alexandria Alliston ... ... Almonte ... Ansonville ... Armstrong Arnprior ... ... Atikokan Aurora ... Bancroft ... Barrie ... Barriefield ... Beaverton ... Belleville ... Belmont ... Bowmanville ... Bracebridge ... Bradford ... Brampton ... Brantford ... Brighton ... Brock'ville ... Brooklin ... Burks Falls ... Burlington ... ... Caledonia Cambridge ... Campbellford ... CampBorden ... Cannington ... CarletonPlace ... Cavan ... Centralia ... Chapleau ... Chatham ... Chelmsford ... Chesley ... Clinton ... Coboconk ... One Day Rain . in . 3.0 2.0 4.0 4.0 4.0 5.0 4.0 3.5 3.5 3.5 3.5 2.0 3.5 3.0 3.0 2.0 3.5 4.0 3.0 3.5 3.5 3.0 3.0 4.5 3.0 2.5 4.0 3.0 3.5 4.0 2.5 5.0 4.5 5.5 3.0 3.5 3.0 4.5 4.5 6.0 4.0 3.0 3.5 3.0 4.0 4.0 4.0 4.0 3.5 4.5 5.0 3.0 3.0 3.5 3.5 4.0 3.0 3.0 3.5 5.0 Design January 21/28. OF -28 -40 -22 -25 -28 -22 -27 -25 -25 -25 -26 -35 -25 -30 -32 -35 -25 -27 -28 -25 4 -2 - 1 l -7 -14 -27 -38 -16 -29 -4 -15 -9 -7 -10 -7 4 -3 -13 -7 0 3 -5 -9 -3 -14 3 4 1 -9 -8 -9 -13 -7 4 -3 1 6 -15 0 4 -12 Gnd . Snow Load. psf 48 38 38 53 46 40 47 45 45 47 45 56 45 52 59 50 45 46 48 45 40 43 58 65 60 69 82 60 65 48 73 60 50 50 50 38 44 69 52 50 48 48 54 44 106 40 46 55 55 65 50 58 52 41 64 27 55 80 50 60 Ann . Tot . Pcpn.. in . 20 16 21 20 19 20 19 20 20 22 20 16 21 17 17 17 20 18 20 20 38 32 37 30 33 30 27 3 1 25 29 30 32 34 34 32 37 32 40 30 3 1 31 32 38 3 1 . 36 31 31 33 31 28 32 33 31 38 30 30 30 35 35 38 Temperature July Dry. OF 82 81 89 86 81 87 85 87 87 85 84 80 87 84 81 80 87 86 82 87 88 87 86 85 86 86 83 87 85 86 84 85 82 86 86 88 86 84 86 87 88 86 85 87 84 88 88 86 87 85 86 86 87 88 82 90 86 86 86 85 1%. OF -30 -43 -25 -29 -30 -25 -30 -28 -28 -28 -29 -38 -28 -33 -35 -38 -28 -30 -30 -28 1 -5
-
16 - 1 1 -18 -32 -44 -20 -34 -8 -19 - 13 -10 -1 4 -1 1 0 -6 -17 -11 -4 -1 -8 -13 -7 -18 0 1 -3 -13 -12 -13 -17 - 1 1 1 -36 3 -20 -4 0 - 16 2% Wet.
OF 73 68 74 73 73 74 73 74 74 74 74 68 74 72 71 69 74 73 73 74 74 75 74 74 74 71 71 74 72 74 73 73 75 73 75 75 75 72 74 75 75 75 75 75 71 75 75 75 74 73 74 74 74 74 7 1 75 70 72 73 73 Seismic Zone 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 1 2 1 2 1 0 2 0 1 1 1 1 1 1 1 1 1 1 1 1 1 2 I 1 2 2 I 1 1 1 2 1 1 1 I 1 1 1 1 O 1 psf 5.9 9.8 8.3 7.0 6.0 7.5 7.5 7.3 7.3 6.5 6.8 10.7 6.5 6.2 7.3 10.1 7.3 7.4 5.9 7.3 8.3 9.0 6.4 4.6 6.2 6.4 4.3 5.7 4.2 6.4 4.8 4.4 7.3 5.0 6.7 7.3 9.6 4.0 5.0 6.6 6.5 8.7 6.6 8.0 4.2 7.5 6.6 5.5 6.1 4.5 5.1 6.2 6.5 7.8 4.0 6.7 6.0 6.9 7.8 4.7 Hourly Wind Pressures.
psf 7.1 12.1 9.9 8.5 7.3 8.9 8.9 8.7 8.7 7.8 8.2 12.6 7.8 7.3 8.9 12.1 8.7 8.9 7.1 8.7 10.4 11.0 7.8 6.1 7.8 7.8 5.1 7.1 5.1 8.2 6.1 6.1 8.9 6.7 8.2 9.4 11.5 5.3 6.7 8.2 7.8 10.4 8.2 9.9 5.5 8.9 7.8 6.7 7.8 6.1 6.7 7.8 8.2 9.9 5.1 8.2 8.2 8 9 9.9 6.1 I'1003 psf 8.6 14.8 1 1.8 10.2 8.9 10.7 10.6 10.3 10.3 9.2 9.9 14.9 9.3 8.7 10.8 14.3 10.3 10.7 8.5 10.3 12.9 13.3 9.4 7.9 9.6 9.4 6.0 8.7 6.0 10.5 7.6 8.1 10.8 8.7 10.1 12.0 13.7 6.8 8.8 10.2 9.2 12.4 10.1 12.2 7.1 10.5 9.2 8.1 9.8 8.1 8.7 9.7 10.3 12.5 6.3 10.1 11.0 11.4 12.5 7.8Copyright
©
NRC
1941
- 2019
World
Rights
Reserved
©
CNRC
1941-2019
Droits
réservés
pour
tous
pays
DESIGN DATA FOR SELECTED LOCATIONS IN CANADA Seismic Zone 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 I 2 I 2 I 0 2 0 I I I I I 1 I 1 1 I 1 1 1 2 1 1 2 ' ' r 2 I I I 1 2 1 I I 1 I Province and Location ... Cobourg ... Cochrane ... Colborne ... Collingwood Cornwall ... ... Corunna ... DeepRiver Deseronto ... ... Dorchester Sta Dorion ... Dresden ... Dryden ... ... Dunbarton ... Dunnville Durham ... Dutton ... Earlton ... ... Edison Elmvale ... Embro ... ... Englehart Espanola ... Exeter ... Fenelon Falls ... Fergus ... Fonthill ... Forest ... FortErie ... Fort Francis ... Gananoque ... Georgetown ... Geraldton ... Glencoe ... Goderich ... Gore Bay ... Graham ... Gravenhurst ... Grimsby ... Guelph ... Guthrie ... Hagersville ... Haileybury ... Haliburton ... Hamilton ... Hanover ... Hastings ... Hawkesbury ... Hearst ... Honey Harbour ... Hornepayne ... Huntsville ... lngersoll ... Jarvis ... Jellicoe ... Kapuskasing ... Kemptville ... Kenora ... KillaloeSta ... Kincardine ... Kingston ... 1 One Day Rain. in . 3.0 2.5 3.0 4.0 2.5 3.5 3.5 3.5 3.5 3.0 3.0 4.0 4.0 4.0 3.0 3.5 3.5 3.5 5.0 3.5 4.0 3.5 3.5 5.2 3.5 4.0 3.5 4.0 3.5 3.5 5.0 3.0 3.5 3.5 2.5 4.0 4.5 4.5 4.5 5.0 4.0 3.5 3.5 4.0 3.0 3.5 3.5 2.5 5.0 3.0 4.0 3.5 4.0 3.0 2.5 3.0 3.5 3.0 3.0 4.5 Ann . Tot . Pcpn.. iri . 32 3 1 32 32 38 32 29 33 36 29 31 25 32 35 35 35 29 25 33 35 29 32 38 32 33 33 34 34 28 36 32 27 35 31 32 27 40 31 33 33 33 29 34 31 36 31 39 28 35 25 36 35 34 28 28 34 25 28 35 34 Seismic Zone 1 1 1 1 2 1 2 1 1 1 1 0 1 2 1 1 1 0 1 1 1 1 1 1 1 2 1 2 0 1 1 0 1 1 1 0 1 2 1 1 1 L 1 2 1 1 2 1 1 0 1 1 1 0 1 2 0 1 1 1 Gnd . Snow Load. psf 45 68 45 85 55 30 56 50 42 68 29 62 42 48 80 32 53 62 75 52 56 55 45 60 85 50 35 55 62 52 55 63 34 50 45 70 62 38 60 56 44 56 75 40 75 55 62 56 80 54 104 46 41 65 56 57 62 55 75 50 Degree Days Below 65OF 7700 1 1412 7700 8400 8200 7000 9500 7500 7400 10800 6800 1 1147 7400 7000 8474 6900 10792 11000 8400 7600 10900 9300 7500 8600 8452 6800 7031 6600 10700 7800 7817 12000 7000 7712 9009 11838 8700 6592 7749 8300 7200 10700 9038 6821 8000 8200 8800 11900 8400 12066 8726 7400 7100 11800 1 1560 8338 10796 9074 7800 7724 Design January 2H%
