Ch. 6 ventilation Flashcards
Stair shafts in high rise building constructed after ____ are required to employ a stair shaft ventilation system
1974
Pressurization fans, that function when the sprinkler or smoke detector systems are activated, are required to provide a uniform air velocity within each enclosed stairshaft. The fans must provide not less than ____cubic feet per minute while maintaining a positive pressure of not over ____lbs. on interior doors
50 cubic ft. Per min
25lbs.
Additionally the pressure generated by a fire (up to ____times atmospheric pressure) will force smoke through these openings and may contaminate other floors or stairshafts within the building.
3
_______ is a condition caused by smoke and fire gases that cannot vertically escape building. Smoke and fire gases will rise to the highest level possible and then begin to bank down and fill all available spaces
Mushrooming
In the City of Los Angeles, windows in exterior walls that can be used for the removal of heat and smoke are required as follows:
Pre 60- openable windows
Post 60- tempered glass on at least ___ sides of building, at corners and ___ ft intervals
Post 74- tempered glass on ____ sides of building, at corners and at ___ ft intervals.
*what may be substitute for tempered glass?x2
Post 60 - 2 sides ; 50ft
Post 74 - all 4 sides; 50ft
*openable windows or smoke removal systems
The natural air flow within a building stairshafts is virtually static in buildings up to _____. Buildings over this will flow minimal amounts of air in which direction.
25 stories; upward
By simply opening a door at the bottom and roof of stair shaft natural air currents of ___ to __ mph can be achieved
3 to 6
Consider the use of Water Turbine Driven Positive Pressure Ventilators, strategically located throughout the Department, if augmentation of the stairshaft is required. Water turbine blowers produce significantly less noise and will provide more than ___the cubic feet of air per minute that a like-sized gasoline powered blower.
Twice
Tempered glass windows are identified by ___ in luminous or reflective decals in lower corner
3in
Pressurize stairwell;
Regardless of the size, portable blowers should be placed ___ ft to __ feet back from doorway and angled at least ____ degrees.
- placing fans in a _____ is more effective than placing them in series.
4 to 6ft; 5 degrees
*v shape
If windows must be opened / broken for ventilation purposes, utilize the windows on the ____ side
Leeward
Cross ventilation operations are effective up to ____ floors.
Above this additional blowers may have to be used
25
