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Stairshaft pressurization systems under various schedules of stair door operation, nonfire/fire conditions, and the fire floor vented with an exhaust fan were investigated in a 10-storey experimental fire tower. The four stairshaft pressurization systems that were tested had overpressure relief features of exit door relief, barometric damper relief, feedback control with fan bypass, and feedback control with variable-speed fan. Tests have indicated that with any one of the stair pressurization systems on and with mechanical venting of the fire floor, the stairshaft was kept smoke free with four stair doors open., Reprinted from: ASHRAE Transactions 1990, v. 96, pt. 2, p. 384-392, ISSN: 0001-2505, Presented at the 1990 ASHRAE Annual Meeting, St. Louis, MO, USA, June 9-13, 1990

Stairshaft pressurization systems were investigated under various schedules of stair door operation and nonfire/fire and summer/winter conditions in a 10-story experimental fire tower. The four stairshaft pressurization systems that were tested had overpressure relief features of exit door relief, barometric damper relief, feedback control with fan bypass, and feedback control with variable-speed fan. Tests have indicated that, under the conditions tested with any one of the stair pressurization systems on, smoke contamination of the stairshaft can be expected when the stair door on the fire floor is open and the fire floor is not vented to the outdoors. Smoke contamination of the stairshaft was prevented when the fire floor was vented by means of outside wall openings; however, the stairshaft was contaminated when one or more additional stair doors were opened., Presented at the 1990 ASHRAE Annual Meeting, St. Louis, MO, USA, June 9-13, 1990

Three stair pressurization systems with overpressure relief features have been tested in a 22-story apartment building and in two high-rise office buildings. Specifically, exit door relief, barometric damper relief, and a feedback control with a variable-pitch blade supply air fan were subjected to open-door tests. The pressure differences across the stair doors and air velocities at the stair door opening were measured., Reprinted from: ASHRAE Transactions 1990, v. 96, pt. 1, p. 951-958. ISSN: 0001-2505, Presented at the 1990 ASHRAE Winter Meeting, Atlanta, GA, USA, Feb 10-14, 1990

An expression is given for the maximum vertical flow in a simple shaft as a result of stack action. It is intended to relate to a simple building and to the evaluation of the airflow necessary to pressurize a building., Reprinted from: Fire Technology, v. 11, no. 1, February 1975, p. 15-22. ISSN: 0015-2684

This paper outlines the methods that have been used to determine the frequencies and modes of vibration of multistory buildings from their wind-induced vibrations. Three buildings of ten, thirty-eight and forty-seven stories were investigated. A simple theoretical model was used to calculate the frequencies of vibration of the buildings; the model was based on the assumption that there was no joint rotation in the building frames. A comparison of the theoretical and measured values of the frequencies showed that this simple model was a realistic representation of only the smaller building. It is concluded that a model that includes joint rotation would be more realistic for the taller buildings. Auto-correlation and power spectrum analysis of the vibration records were used to obtain an estimate of the damping characteristics of the buildings. The values obtained were 1 to 3 per cent of the critical amount of damping.

The hazard of fire propagation across a wall or floor has been found to be very real in the case of many pipe-floor penetrations and in the case of pipe-wall penetrations under adverse air pressure differentials and where the system on the unexposed side of the wall is vented., Reprinted from: Fire Technology, v. 9, no. 1, February 1973, p. 5-14. ISSN: 0015-2684

The time necessary to evacuate today's high-rise buildings in a fire emergency is unsatisfactory from the standpoint of the development of untenable smoke conditions. The Division of Building Research has been working on the problem for several years and suggests several approaches to controlling smoke movement in buildings., Reprinted from Fire Technology, vol 6(4), November 1970, p. 292-304..

La flambage et l'effritement des placages et des parements de briques des murs creux des immeubles de grande hauteur, sont attibuables aux mouvements des immeubles. Dans certains cas, des pans entiers de facades de parement se sont écroulés. Le présent bulletin traite des caractéristiques des défaillances observées sur nombre de bâtiments et commente certains détails de construction qui ont tendance à créer des problèmes.

This computer program has been prepared to assist in evaluating smoke control measures operating under various conditions caused by weather, fire, evacuation of occupants and fire-fighting. Such studies can assist in developing more effective measures and more efficient procedures for evacuation. The program calculates smoke concentrations for various fire situations in all compartments of a tall office building with a fire on a particular floor. It takes into account the effects of outside weather (wind and stack action), the progress of a fire, the air leakage characteristics of wall and floor constructions, the operation of stair and elevator doors and the operation of the smoke control system. It is composed of two main subroutines; one for calculating air flow rates and the other for calculating smoke concentrations.

Venting the fire region of a building to the exterior significantly reduces smoke problems caused by a fire. This is often achieved by means of a smoke exhaust shaft with dampered openings on each floor. In the event of fire, the dampers at the top and on the fire floor are opened to exhaust smoke to the exterior. The performance of the smoke exhaust shaft is seriously affected by any extraneous air leakage through closed dampers located on the non-fire floors. Tests have been conducted before and after fire exposure to measure the air leakage characteristic of proprietory fire dampers currently used for smoke shaft application. The pre-fire test ratios of leakage area to damper area were generally below 2.5%. After exposure to the standard time-temperature, the ratios were generally below 4%. Restricting the maximum furnace temperature to 1000 degrees F (540 degrees C) considerably reduced the increase in leakage area ratio due to fire exposure., Reprinted from: ASHRAE Transactions, v. 90, 1984, Part 1B, p. 647-654. ISSN: 0001-2505

In recent years, the possibility of using elevators as a means of fire escape has received considerable attention. This interest has been sparked by an increased awareness of life safety problems of the handicapped and also general fire evacuation problems of high-rise buildings. The use of elevators as a means of fire evacuation is a potential solution to this problem. The major technical obstacle to this is smoke contamination of elevator lobbies and shafts. This paper discusses elevator smoke control systems including criteria for evaluation and presents an analysis of airflow due to elevator car motion. Computer analysis of several elevator smoke control systems are included for several combinations of open and closed doors and for summer and winter conditions., Reprinted from ASHRAE Transactions 1986, vol. 92, part 1A, p. 231-245., 1986 ASHRAE Winter Meeting, January 19-22, 1986, San Francisco, California, USA

A model apartment building was developed based upon surveys and computer simulations determining the effects of climate and size on energy consumption. A norm was derived for the energy consumption of any high-rise residential building at any location in Canada. Possible reductions in energy consumption resulting from inexpensive modifications in four existing buildings were also determined., construction

A sprinkler-system controls the amount of smoke generated by fire as well as its spread, and should therefore be considered as a smoke control measure. Separate smoke control systems are often, however, included in the fire safety systems of sprinklered contemporary buildings to handle the smoke generated prior to activation of the sprinkler heads and subsequently from the sprinklered fire. A sprinkler system can also reduce the probability of window breakages by controlling fire temperature. If, as a result, it can be assumed that the exterior walls of the fire floor will remain intact, a smoke shaft with an exhaust fan at the top can ensure effective smoke control. The results reported are of tests conducted on a smoke control system of this type for a 34-story office building equipped with a light hazard sprinkler system.

This paper by Takeshi Goto summarizes extensive Japanese studies on human response to horizontal sinusoidal motion with periods of 1 - 10 seconds and amplitudes of 1 - 50 cm. The results are interpreted in biomechanistic terms as a basis for establishing habitability criteria.

By applying the pressure data obtained from a wind tunnel model study to a computer model building, a simple procedure for calculating exterior wall pressure differences and air infiltration rates for various wind velocities and direction was developed. This study has indicated that the overall infiltration rate is governed by the larger of the two motive forces and that the exterior wall pressure differences at any level caused by wind and stack action are additive., Presented at the 1977 ASHRAE Annual Meeting, Halifax, NS, Canada, June 26-30, 1977

Little information exists on the pressure drop characteristics of stairshafts in tall buildings. Full- scale tests were conducted, therefore, to develop data on the airflow resistance required for designing a smoke control system for stairshafts by the pressurization technique. Data were obtained for open and closed tread stairshafts, with and without people inside them. The study revealed that the flow resistance inside the stairshaft with people can be double that without people. Also, a simple physical model to simulate the effect of people on the flow resistance was developed. This paper describes the analytical model, the experimental study, and the data obtained on the airflow resistance for the various stair configurations., Presented at the ASHRAE Winter Meeting, Dallas, TX, USA, Jan 31-Feb 3, 1988

A stochastic risk-cost assessment model is presented for multi-storey apartment buildings. The model can be used to assess the relative fire risks and fire costs of alternative fire protection designs in comparison with designs based on current building code requirements., Reprinted from: Proceedings of the International Symposium on Fire Engineering for Building Structures and Safety, Melbourne, Australia, November 14-15, 1989, p. 15-19., International Symposium on Fire Engineering for Building Structures and Safety, November 14, 1989, Melbourne, Australia

The National Research Council of Canada has taken measurements of the air leakage characteristics of the exterior walls of eight multi-storey office buildings located in Ottawa, Canada. Varying in height from 11 to 22 stories, with curtain wall construction and fixed glazing, they were built during the sixties and early seventies. The results of the measurements are reported in this paper. A method for calculating infiltration rates caused by stack action has been developed and is applied to heat loss calculations using the measured wall leakage values., Les auteurs présentent des valeurs mesurées d'étanchéité à l'air pour huit tours de bureaux (murs-rideaux et vitrages scellés). Ces valeurs sont de beaucoup supérieures aux valeurs mentionnées dans norme industrielle. Une équation permettant de calculer la vitesse totale de pénétration due à l'appel d'air est appliquée aux édifices à l'aide de valeurs mesurées de l'étanchéité à l'air des murs. Les auteurs examinent également le rôle que joue la pénétration de l'air dans la perte globale de chaleur, y compris la transmission et la ventilation mécanique., Reprinted from ASHRAE Transactions, vol. 82, part 1, 1976, p. 122-134., Réimprimé du "ASHRAE Transactions, vol. 82, part 1, 1976, p. 122-134"., 1976 ASHRAE Semi-Annual Meeting, February 1-5, 1976, Dallas, Texas, USA, 1st AIC Conference: Air Infiltration Instrumentation and Measuring Techniques, October 6, 1980, Berkshire, UK

Occupants of highrise buildings are seriously endangered by the spread of toxic smoke in the event of a fire. Both past and continuing research studies on smoke movement and control used mathematical models and field studies conducted in buildings to assess the smoke hazard under various fire conditions. Techniques of smoke control have been developed to provide safe escape routes and refuge areas. Further investigation at the DBR experimental fire tower will examine the effect of fire temperature on smoke movement and the effectiveness of smoke control techniques., Presented at the 1983 ASHRAE Winter Meeting, Atlantic City, NJ, USA, June 23-26, 1983

Movement of people on exit stairs and other egress facilities has been documented in evacuation drills of high- rise office buildings and in the course of normal egress movement in other buildings. Crowd densities, speeds, and flows are described. The findings raise questions about concepts and specific design rules for exit facilities now given in codes and design guides. More realistic predictions of evacuation time are proposed for conventional total evacuations. Other more selective forms of evacuation, to be workable, require greater concern for new building equipment systems and operating procedures. The need for information concerning human behavioral factors is stressed., Reprinted from Human Response to Tall Buildings, chapter 21, p. 281-292. Community Development Series, vol. 34, 1977. .

Preliminary findings of observations of 40 high-rise office building evacuation drills carried out in Canada have helped to clarify crowd movement characteristics and other factors affecting fire emergency procedures. They raise questions concerning current design and regulatory practices and suggest new standards for means of egress., Reprinted from ASHRAE Transactions 1975, vol. 81, part 1, p. 528-534.

This Digest reviews the effect of wind on people and discusses wind speed changes induced by buildings. Mechanical effects that make it difficult to walk and the thermal effects of wind are considered.

Full-scale pressure coefficients obtained from a 57-storey building in Toronto and wind tunnel results from tests in the 9 m by 9 m wind tunnel at the National Research Council of Canada are compared and demonstrate good agreement where sufficient full-scale data exist. A method of treating peak pressures is proposed based on the fit of an exponential distribution to a population of "significant independent events," called pressure spikes. This distribution provides a good fit to both full-scale and wind tunnel results, which generaly agree., 5th International Conference on Wind Engineering, July 8, 1979, Fort Collins, Colorado, USA

Studies were conducted on exterior wall venting in the context of the building pressurization approach to smoke control. It was shown that the venting rate depends on the amount of building pressurization, vent area and the leakage area of the floor enclosure. Tests on two multi-story buildings indicated that a vent area equal to one percent of the total exterior wall area of the vented floor approximated the maximum venting rate. At this rate, the favorable pressure differences across the fire floor enclosure are at their highest values and are just a little less than one-half of the building pressurization with no venting. Tests also indicated that wind is unlikely to seriously affect the venting performance except for the case with wall vents opened only on the windward wall., Reprinted from ASHRAE Transactions, vol. 84, part 2, 1978, p. 204-215., 1978 ASHRAE Annual Meeting, June 25-29, 1978, Albuquerque, NM, USA

Recent high-rise concrete buildings contain load-bearing walls and rectangular concrete columns that may be subjected to fire on more than one side. Existing fire ratings for these members, based on a fully loaded square column exposed to fire on all sides, appear to be excessively conservative. Analytical studies based on temperature-dependent material properties can be used to calculate temperature, stresses, movements, constraint forces and strength of a structure during fire and to replace costly fire tests for determining fire resistance. Such a study was carried out for reinforced concrete columns and walls and new fire ratings determined. The paper discusses the effect of structural interaction and spalling on fire resistance and the relation of fire resistance requirements to the general problem of fire safety, particularly for high-rise buildings., Canadian Structural Concrete Conference, June 1977, Ottawa, Ontario, Canada

Surveys were conducted in Toronto and Calgary to obtain information on current practice in smoke-control systems in high-rise buildings. The surveys revealed that most office buildings and hospitals are fully sprinklered, occasionally together with stair and elevator shafts protected by mechanical pressurization. In most office buildings the mechanical ventilation system is designed to be used for exhausting smoke from the fire area. In most apartment buildings under 36 m high, balconies are used as refuge areas; over 36 m high, pressurized stair and elevator shafts are common. Provisions are made in some instances for mechanically pressurizing the corridors to assist in confining smoke to the fire compartment., Reprinted from Engineering Digest, vol. 30(7), August 1984, p. 32-34.

Pressure and tracer gas measurements for a 15-story hotel in winter (when the building was under the influence of stack action) are used to assess the smoke hazard associated with fire. Tracer gas was released continuously to simulate generation of cold smoke in the fire room. With fire on the ground floor, the stair and elevator shafts and the upper floors became smoke filled in a very short time. With fire in a room on the second floor, the hotel remained relatively uncontaminated provided that the exterior wall of the fire room remained intact and the room entrance door remained closed. The extent of contamination increased significantly, however, when an opening in the exterior wall was created to simulate a broken window. Contamination increased further when the room entrance door was also opened and increased still more when the stair door on the fire floor was open. Measurements of pressure differences and airflow direction were made with the stair and elevator shaft pressurization systems in operation. Because of the indirect pressurization of the corridors by these systems, smoke from the fire room will probably be prevented from contaminating the remainder of the building., Presented at the 1985 ASHRAE Annual Meeting, Honolulu, HI, USA, June 23-26, 1985

Tests were conducted in winter on the mechanical vestibule protection system of a seventeen-story apartment hotel tower situated in Ottawa and built in 1974. The system was designed to protect from smoke contamination a stair shaft and a two-car elevator shaft located at one end of a corridor. The performance of the protection system was evaluated by measuring air flow and pressure with a view to drawing diagrams of pressure and air flow patterns in the building that could be used to predict the probable behaviour of smoke during a fire. The tests indicated that the vestibule pressurization system would provide effective protection against smoke contamination of the elevator and stair shafts., Reprinted from ASHRAE Transactions, vol 86(1), 1980, p. 593-603., 1980 ASHRAE Semi-Annual Meeting, February 3-7, 1980, Los Angeles, California, USA

Based on studies conducted by the Division of Building Research, the authors analyzed the most important factors that determine expectation of life loss from smoke in high- rise buildings., Reprinted from Fire Technology, vol 11(1), February 1975, p. 5-14.

Venting is an effective way to prevent smoke from spreading from a fire area into escape routes and upper floors of high- rise buildings. A smoke exhaust system consists of a vertical shaft with dampered openings on each floor ( normally closed) and an exhaust fan at the top of the shaft. In the event of fire, the damper on the fire floor is opened and the exhaust fan operated to vent the fire floor. This induces air from the surrounding spaces to flow into the fire floor enclosure and the smoke to exit through the exhaust shaft to outdoors. Such a system requires the proper size of smoke shaft and exhaust fan capacity. A simplified design procedure and example calculations are presented. Measured and calculated values are in good agreement for total pressure loss and exhaust rate of a smoke exhaust system for a 34-story office building., Presented at the 1985 ASHRAE Annual Meeting, Honolulu, HI, USA, June 23-26, 1985

Buckling and spalling of brick veneer and brick facing wythes of cavity walls on highrise buildings are attributable to building movements. In some instances the facing of whole panels has fallen off. It is the purpose of this Digest to discuss characteristics of failures observed in a number of buildings and to comment on particular details of the forms of construction that tend to contribute problems.

Measurements made on two buildings reveal that leaky wall construction of a smoke shaft can seriously affect the performance of a smoke control system. Also revealed is that a stairshaft can be contaminated with smoke, particularly in summer when the stair door on the fire floor and the exit door of the same stairshaft are opened at the same time., Reprinted from ASHRAE Journal, vol. 23(2), February 1981, p. 21-25.

A computer study of smoke movement using a mathematical model of a 20-storey building is described. The model is based on measured air leakage characteristics of four tall office buildings. The results indicate the relative influence of a number of features governing smoke movement in buildings. Smoke concentration patterns caused by stack effect are determined for both steady and transient conditions., Reprinted from ASHRAE Transactions, vol. 75, Part II, 1969, p.81-92., 1969 ASHRAE Semi-Annual Meeting, June 30 - July 2, 1969, Denver, Colorado, USA

Air that leaks through the exterior envelope of a building is a significant component of the heating, cooling and moisture loads of heating, ventilating, and air-conditioning systems. The prediction of air migration routes and flow rates within a building is also important in relation to the control of contaminants, such as smoke and odours. This paper describes a procedure for calculating air flows and pressure differentials that will occur in a multi-storey building as a result of a combination of wind effect, stack effect, and operation of air-handling systems., 2nd Symposium on the Use of Computers for Thermal Environmental Engineering, 1974, Paris, France

Stack effect in a building depends on the difference in the temperatures of inside and outside air and the height of a building. The influence of stack effect is significant, particularly in tall buildings, during the winter seasons. This Digest describes the distribution of the total pressure difference caused by stack action across a building enclosure and interior separations and the many implications of the resulting air flow patterns., Canadian Building Digest, CBD-104

Wind pressure records ranging in length from 15 minutes to about one hour, taken from twelve simultaneously recorded pressure transducers located at two levels in a 400 ft high office building in downtown Montreal were analysed to determine mean pressures, variances, spectral functions, and for selected pairs of transducers, cross-spectral functions. The measurements were made during five different windstorms in the period from 5 March 1964 to 2 March 1966. Most of the pressure measurements are supplemented by simultaneous recordings of wind direction and wind speed at 800 ft height from a wind vane and anemometer at a nearby location. The paper provides information on the relation between turbulence in a strong wind in a city environment and the wind pressure fluctuations on an actual building. Preliminary work in co-operation with the University of Western Ontario to compare the full-scale measurements with wind-tunnel measurements indicates that successful simulation of the basic statistical properties of wind pressure fluctuations can be obtained through the use of model complexes in a boundary layer type of wind tunnel., International Research Seminar on Wind Effects on Buildings and Structures, September 1967, Ottawa, Ontarion, Canada

Wind-induced vibrations in multi-storey buildings are utilized to determine foundation stiffnesses as well as structural modal properties. Two methods are presented which permit the determination of foundation stiffnesses, both rocking and in the horizontal direction, by combining experimental data with theoretical calculations. One method employs modal frequency ratios for the entire system; the other employs modal amplitude ratios. A quantitative assessment of the restraint on a large raft foundation of a 12 storey reinforced concrete building is given., Reprinted from Proceedings, The Institute of Civil Engineers, September 1972, vol. 53, p. 305-322.

The buildings considered are assumed to conform to a building code such as the National Building Code of Canada being, for example, adequately compartmented. It is suggested that a criterion for the tenability of an atmosphere might be that its optical density per metre should not exceed some value between 0.05 and 0.l. A calculation of the amount of material needed to smoke-log a building is quoted. The objective of the smoke control measures developed by DBR is described. Some general approaches to the problems created by shafts are reported. The effects of lowering shaft pressures by top venting and of raising them by bottom venting and air injection are discussed. Finally the merits of dispersing smoke by dilution, particularly in warm weather, are debated., Reprinted from ASHRAE Symposium Bulletin "Fire Hazards in Buildings", 1970, p. 8-13., Symposium on Fire Hazards in Buildings, January 19, 1970, San Francisco, California, USA

The authors describe the results of field studies to measure overall air leakages and the pattern of pressure differences caused by the chimney effect, both alone and in combination with building ventilation systems. The zone in which the interior pressure equalled the exterior pressure in the buildings was at a level ranging between 35 and 52 per cent of building height. Pressure differences across entrances were lower with ventilation systems off than would be calculated from the ASHRAE Handbook because of the low height of the zero pressure-difference zone and the significant pressure losses across first-floor ceilings. The ratio of actual to theoretical draft varied between 0.6¤ 3 and 0.82.andThis paper describes the results of a study on the pattern of pressure differences caused by the chimney effect and mechanical ventilation. For this purpose, the authors used a mathematical model representing a building. They determined the effects of variations in airtightness of the exterior walls and partitions and of the number of storeys on the pattern of pressure differences. They also examined the way in which imposed pressure differences, whether uniform or not, affect the pattern of pressure differences caused by the chimney effect. These data provide the basis for the prevention of air leakages caused by chimney action. They also help in interpreting the practical measures referred to in the companion paper entitled " Pressure Differences Caused by Chimney Effect in Three High Buildings"., Les auteurs exposent les résultats de recherches menées sur place en vue de mesurer les fuites totales d'air et la ré partition des pressions engendrée par l'effet de tirage, tant seul qu'en conjonction avec l'appareillage de ventilation des immeubles. La région des édifices où la pression interne égalait la pression externe atteignait de 35 à 52 pour cent de leur hauteur. Les différences de pressions de part et d'autre des entrées étaient plus faibles lors de l'arrêt de l'appareillage de ventilation que le manuel de l'ASHRAE ne permettait de les calculer, en raison de la faible altitude de la région à différence pié zométrique nulle et des importantes pertes de pression aux plafonds du rez-de-chaussée. La proportion centésimale du tirage réel par rapport au tirage calculé atteignait entre 0. 63 et 0.82.etLe présent article communique les résultats d'une étude sur la répartition des différences de pressions engendrées par l' effet de tirage et la ventilation méchanique. Les auteurs se sont servis pour cette étude d'un modèle mathématique représentant un bâtiment. Ils ont déterminé les effets de variations d'étanchéité des murs extérieurs et des cloisons et du nombre des planchers sur la répartition des pressions. Ils ont également étudié la manière par laquelle l'établissement de différences de pressions uniformes ou non affecte la répartition des pressions causées par l'effet de tirage. Ces données fournissent la base de la prévention des fuites d'air causées par l'effet de tirage. Elles aident également à interpréter les mesures pratiques contenues dans l'article conjoint intitulé "Différences de pressions causées par l'effet de tirage à l'intérieur de trois édifices élevés.", Reprinted from ASHRAE Transactions 1967, vol. 73, part II, no. 2046 and no. 2047., Réimprimé du "ASHRAE Transactions 1967, vol. 73, part II, no. 2046 and no. 2047"., 1967 ASHRAE Annual Meeting, June 26-28, 1967, Minneapolis, MN, USA

In the past five years, a number of high-rise apartment buildings have been erected in Western Canada that incorporate non-loadbearing exterior steel frame walls. Steel-stud manufacturers have recently been pressing for the acceptance of these walls for more general use in residential construction. A major consideration in determining the acceptability of steel wall systems for cold- weather regions is their thermal performance. In order to provide a rational basis for acceptance and to assist the designers of steel wall systems, the Division of Building Research undertook laboratory and field investigations on the thermal performance of steel frame walls. The results of the field investigation on a number of existing buildings are presented in this paper., Reprinted from Specification Associate, vol. 13(6), November - December 1971, p. 21-35.

Design methods based on a statistical approach to the prediction of dynamic effects of wind on frameworks of tall buildings are steadily gaining acceptance. Similar concepts can be applied to wind loads on cladding, although there are important differences such as exposure, size, and dynamic properties of the elements considered. Wind pressures and suctions at several points on a tall building recorded during strong winds are used to study the problem of predicting peak gust loads on windows and cladding elements. The statistical approach to the prediction of peak gusts, based on random process theory, is investigated. Measured peak pressures are compared to values calculated by a simple wind gust factor method and by a more detailed gust effect factor method. It is concluded that the gust effect factor method is preferable because it promotes a better understanding of peak pressures, but further field data and experimentation are needed before entirely satisfactory design estimates can be made.

The authors determined the pressure differences caused by wind action across the walls of a 44-storey building and a 34-storey building in the centre of a large city. They did a regression analysis of the pressure records to determine the wind pressure coefficients for the two buildings. The coefficients varied considerably with variations in direction of the vertical wind velocity gradient and the shielding effect of adjacent buildings. The on-site wind speeds recorded were compared with wind velocities measured at the meteorological station. It was found that the relationship between the two observations varied with the general configuration characteristics of the terrain at the two locations., Presented at the 1968 ASHRAE Annual Meeting, Lake Placid, NY, USA, June 24-26, 1968

Air leakage through the building envelope is an important consideration in the control of air conditions in buildings. It also affects the way that smoke or other contaminants migrate within the building and hence directly influences the design of systems that are intended to control or inhibit the movement of contaminants. Tests have been carried out on contemporary high-rise buildings to obtain data on their air leakage characteristics. Field studies have been complemented by the development of a computer program for calculating the air flow rates and pressure distributions that may occur under various combinations of wind and stack effects. These studies are described and the implications of the results on building design are discussed., 6th CIB Congress, The Impact of Research on the Built Environment, October 3, 1974, Budapest, Hungary

The current status of North and South American research on the prediction of tall building behaviour in response to wind is reviewed under the headings, meteorological research on wind structure and climate, full-scale tests, development of wind tunnel techniques, and simplified prediction formulae for gust effects. The need for cooperation in gathering and applying both full-scale and wind tunnel data is stressed. Over forty references published in the last ten years are given, arranged chronologically under each of the four main headings., International Conference on Planning and Design of Tall Buildings, August 1972, Pennsylvania, USA

In the event of fire in the lower levels of a high-rise building, the upper floors and escape routes can become contaminated with smoke very quickly and in less time than is required to evacuate the building. Control of smoke is therefore an important consideration in the design of buildings.

In many countries structural design procedures are undergoing changes toward recognition of "limit states", e. g., excessive deformation, unserviceability, collapse. The application of this philosophy has two prerequisites: first, design loads and material properties must be defined on a more realistic (probabilistic) basis; second, design safety rules and factors must be related more closely to risk and consequences of failure. The Division of Building Research of the National Research Council of Canada, in recognition of these trends, has carried out extensive field observations and studies of loads, particularly snow loads on roofs and wind pressures and suctions on walls of high- rise buildings. The paper describes briefly the major features of this work, including observation methods and some of the results., 6th CIB Congress, The Impact of Research on the Built Environment, October 3, 1974, Budapest, Hungary

Some of the features of wind near the surface of the earth are briefly described in this Digest. Particular attention is given to gustiness and to the rates of increase of both mean wind speeds and peak gust speeds with increases in height. A method of computing design wind speeds from wind observations available in Canada is outlined.