Pressure

a) Negative Pressure	e) Positive Pressure
b) Pressure, Absolute	f) Pressure, Atmospheric
c) Pressure, Gauge	g) Pressure, Static
d) Pressure, Total	h) Pressure Drop (Differential Pressure, *P)

1. Condition that exists when more air is supplied to a space than is exhausted, so the air pressure within that space is greater than that in surrounding areas. Under this condition, if an opening exists, air will flow from the positively pressurized space into surrounding areas.

2. It is a term used to characterize the reduction in air pressure between any two points in the ventilation duct network. It occurs as the compressed air travels through filters and ducts. In airflow system, the energy is measured as "pressure drop."

3. The total pressure measured in relation to a perfect vacuum. The sum of atmospheric and gauge pressures.

4. Condition that exists when less air is supplied to a space than is exhausted from the space, so the air pressure within that space is less than that in surrounding areas. Under this condition, if an opening exists, air will flow from surrounding areas into the negatively pressurized space.

5. The force exerted by the weight of the atmosphere on a given area. It is measured in units of pascals (Pa) or torr (millimetres of mercury). The normal atmospheric pressure is 760 torr or 101 kilopascals (kPa).

6. Instruments used to measure pressure are called pressure gauges. Generally it gives air pressure relative to atmospheric pressure. It can show a negative pressure (less than atmosphere), or positive (greater than atmosphere.)

7. In flowing air, the total pressure minus velocity pressure. The portion of the pressure that pushes equally in all directions.

8. In flowing air, the sum of the static pressure and the velocity pressure.

D. Give the Russian equivalents to the following abbreviations.

1) CFM (cubic feet per minute) - _______________________________

2) HEPA (High-Efficiency Particulate Air Filter - a filter designed to remove 99.97% of specific type particulate material (0.3 micrometers in diameter) from air) - _________________________________________

3) HVAC (Heating, ventilation, and air-conditioning system) - _______

4) IAQ (indoor air quality) - ___________________________________

5) VOCs (Compounds that vaporize (become a gas) at room temperature. Common sources which may emit VOCs into indoor air include housekeeping and maintenance products, and building and furnishing materials. In sufficient quantities, VOCs can cause eye, nose, and throat irritations, headaches, dizziness, visual disorders, memory impairment; some are known to cause cancer in animals; some are suspected of causing, or are known to cause, cancer in humans.) - ______________________________________________________

E. Match the terms with their definitions. Translate them into Russian.

a) fan	d) capture velocity	g) diffusers and grillers
b) hood	e) drain tile loop	h) environmental agents
c) building envelope	f) odour threshold	i) oxygen deficiency

1. Elements of the building, including all external building materials, windows, and walls, that enclose the internal space.

2. The air velocity required to capture suspended dusts or aerosols and draw them into an exhaust hood.

3. Components of the ventilation system that distribute and return air to promote air circulation in the occupied space. Supply air enters a space through a diffuser or vent and return air leaves a space through a grille.

4. A continuous length of drain tile or perforated pipe extending around all or part of the internal or external perimeter of a basement or crawlspace footing

5. Conditions other than indoor air contaminants that cause stress, comfort, and/or health problems (e.g., humidity extremes, drafts, lack of air circulation, noise, and over-crowding).

6. A device designed to contain and/or capture aerosols and direct them to the exhaust duct network.

7. A mechanical device which causes air movement.

8. The lowest concentration of an air contaminant that can be detected by smell.

9. Concentration of oxygen in the ambient air of less than 19.5% by volume.