All internal combustion engines produce exhaust gases containing noxious compounds: carbon monoxide (CO), nitrogen oxides (NOx, carbon oxides (CxHy) and smoke. With the help of a mathematical model the concentrations of some dangerous substances at the end of the tunnel were calculated, and were replaced by a criteria! number. A corresponding computer program was also developed thus enabling quick and simple calculations of some concentrations and the criteria! number.

The terrifying organisms that live in our ventilation systems have perfected their methods of attack, but Martyn Love thinks he might have the answer          

This Update discusses the various factors that affect sound transmission through different types of concrete block walls, including single-leaf walls, double-leaf walls and walls with gypsum board attached. Knowledge of these factors will assist construction practitioners to design and build walls with high levels of acoustic performance economically.

This Update examines various fire-stopping techniques that meet the intent of the National Building Code of Canada (NBC) with respect to fire resistance and that do not adversely affect the sound isolation of the wall assembly. The information is derived from the results of an industry-sponsored consortium project led by the National Research Council's Institute for Research in Construction (IRC).      

This American National Standard describes procedures for the measurement of sound pressure levels in the outdoor environment, considering the effects of the ground, the effects of refraction due to wind and temperature gradients, and the effects due to turbulence. This standard is focused on measurement of sound pressure levels produced by specific sources outdoors. The measured sound pressure levels can be used to calculate sound pressure levels at other distances from the source or to extrapolate to other environmental conditions or to assess compliance with regulation.

Unless requirements are laid out in codes, control of noise in buildings is often an afterthought. The measures taken to control noise, however, are invariably linked to other building subsystems. Mechanical and plumbing subsystems generate noise; the design of walls, ceilings and floors affects sound transmission.

This paper addresses four topics:

Most of the existing emission models developed from small-scale chamber tests assume complete mixing in the chamber throughout the test period. This paper examined this assumption using a Computational Fluid Dynamics (CPD) model. The model simulated the three-dimensional air velocity profiles and Volatile Organic Compound (VOC) concentration distributions from wood stain in a well-designed mixing chamber of 1.0X0.8X0.5 m3. The model used measured data to determine the time-dependent voc surface concentrations of wood stain.

This report provides the results of a two-phased study conducted for the Canada Mortgage and Housing Corporation (CMHC) to examine the practices and variability amongst practitioners of contaminated sites risk assessment in Canada. Phase I consisted of a survey of practitioners in the private and regulatory sectors. The intent of the private sector survey was to characterize the capabilities and experience of private firms engaged in human health risk assessment across Canada.