2017-11-01
409
Conference rooms or training spaces often have intermittent occupancies. Provided that peak occupancies are of less than three hours duration, the Standard allows that the outdoor air requirement of the space be calculated on the basis of the average occupancy. However, the outdoor air may never be below one-half the maximum. Alternatively, ventilation in these spaces may be increased and decreased as occupancy increases or decreases, but even when unoccupied, the outdoor air ventilation should never be less than necessary to dilute building related contaminants.
Thermal Comfort Requirements
Thermal Environmental Conditions for Human Occupancy, identifies many factors that influence thermal comfort and the perception of thermal conditions. Among them are temperature, radiation, humidity, air movement, vertical and horizontal temperature differences, temperature drift, personal activity and clothing.
Humidity and Microbial Growth
In addition to thermal comfort, the control of relative humidity is important to limit the growth of microorganisms such as mold and dust mites. To control microorganisms, it is best to keep relative humidity below 60% (to control mold) and 50% (to control dust mites) at all times, including unoccupied hours. High relative humidity can foster proliferation of mold and dust mites.
Glossary
Abbreviations:
Adj.= adjective- имя прилагательное/ прикметник
Adv.= adverb- наречие/ прислівник
Pl.=plural- множественное число/ множина
pp.=past participle- причастие прошедшего времени / дієприкметник
n.= noun- имя существительное / іменник
v.= verb-глагол/ дієслово
| outdoor air (n) | наружный воздух | зовнішнє повітря |
| the amount (n) | количество | кількість |
| deterioration (n) | ухудшение | погіршення |
| load conditions (n) | условия нагрузки | умови навантаження |
| flow rates (n) | скорости потока | швидкості потоку |
| humidity (n) | влажность | вологість |
| dilute (v) | разбавлять | розбавляти |
| mold (v) | плесень | цвіль |
| dust mites (n) | пылевые клещи | пилові кліщі |
| foster (v) | способствовать | сприяти |
| in addition to (adv) | в дополнении к | у доповненні до |
| duration (n) | продолжительность | тривалість |
| outdoor air volume (n) | объем наружного воздуха | обсяг зовнішнього повітря |
| contaminants (n) | загрязняющие вещества | забруднюючі речовини |
Major terms
Constant air volume (CAV)
A system designed to provide a constant air volume per unit time. This term is used in HVAC systems that have variable supply –air temperature but constant air flow rates. Many residential forced-air systems are small CAV systems with on/off control.
Variable air volume (VAV) system
An HVAC system that has a stable supply-air temperature, and varies the air flow rate to meet the temperature requirements. Compared to CAV systems, these systems waste less energy through unnecessarily-high fan speeds. Most new commercial buildings have VAV systems.
