AUC 349 + ADD Flashcards
What do Positive Pressure Fans do & what can it be used on?
Pressurize attack & evacuation stairwells to keep heat & smoke from entering stairwells or to vent the bldg. Works on smoke & CO
The 1st consideration for PPF is _ stairway
Attack Stairway: FFs should be notified via HT & Dispatcher when attack stairs designated
Priority Order for use of PPF (3)
Pressurizing Attack Stairway to support fire attack throughout attack stairway, Pressurizing Evac stairs for smoke & CO control, & Vent public hallways for smoke & CO control
The initial location for PPF should be _
Ground floor- try to utilize an exterior door to reduce noise & CO levels for ICP
If units are committed on fire fl but extreme smoke condition of stairwell- PPF can _
Pressurize ground fl w/fire fl door closed as much as possible for HL. Vent Group Roof FF shall burp bulkhead door open until smoke clears approx 60 sec & shut bulkhead. Pressurization maintains in stairwell w/bulkhead open or closed
If CO levels are in the - ppm range, gas powered PPF will NOT significantly reduce CO levels
0-60 PPM
What can be used to create Negative Pressurization?
Negative pressure is beneficial in _ areas
Lad Cos electric box fan operated in exhaust mode to remove contaminated air
Below grade areas
Ladder Cos that carry PPF are designated _ & report to _
The Off of PPF is designated
Ventilation Support Group Companies; ICP
Ventilation Group Supervisor
Once PPF put in operation, can they be left unattended?
Never unattended- HT equipped FF must continually monitor-Dave Clark set
Pushing fresh air into areas that need to be pressurized or ventilated is preferred method for positive pressure vent. Optimum placement is _
4-6’ from Attack stairway door on ground floor (NOT in stairway) & directly facing the door to stairwell at an angle tilt of 80 degrees
Fire above the _ floor- add’l PPF req’d & set up __
Above 10th fl; 3 Flrs below & set up same as 1st fan 4-6’ back 80 angle (NOT in stairwell)
Sequential Ventilation: after fire ext remove products of combustion vertically through _ by placing a fan at the base of _. Keep the bulkhead of _ stairway open & _ closed. Open stairwell doors on fire floor for _ stairway.
Attack Stair;
base of Evac Stairwell;
Attack bulkhead open & Evac closed;
Both doors to cross vent
Does wind have to be considered when using PPF?
Yes Wind must ALWAYS be considered
During Negative pressurization, if a box fan cannot be hung or tarps not available, position fan inside contaminated area facing exhaust opening _ feet back tilted _ degrees
6-8’ approx 30 degree tilt
PPF shall be dispatched on signal _ &
10-77 & special called by IC
Can the Vent Support Group Supervisor initiate stairwell pressurization?
No only IC can. Vent Group Supervisor informs IC of recommended placements of PPF
1 fan can provide proper pressure in stairwell up to _ stories & 2 fans will pressurize _ story bldg
10; 40
Does the PPF in the attack stairwell provide an uncontaminated area of refuge for members?
Yes
PPF are great enough to allow up to _ stairwell doors to be open & pressurization to remain effective
Up to 3, but keeping as many doors closed as possible is the goal (even if HL stretched close door as much as possible)
The members assigned to operate the fans are designated
Ventilation Group Lobby Unit, Vent Group Fire Unit, Roof FF: Vent Group Roof
PPF inspected _
Inspected & started daily 9X6 tour. Weekly at MUD full RPM run for 5 min along w/visual inspection. Repairs to Tech Services
Extreme smoke condition in Attack Stairwell (how do you remove)
When units NOT committed on fire fl- PPF on ground fl & Vent Roof FF shall open bulkhead (burp) approx 60 sec & shut bulkhead. Stay at bulkhead position
One 27” gas powered fan moves approx _ times more air than 16” electric box fan
approx 5 times (24,000 CFM)
The fan should be positioned to blow (into/out) of stairwell & (should/should not) be placed in stairwell
Into; Should NOT- may create high CO levels & negative stack effect by pulling smoke & heat
How many FF to lift PPF?
Two members
The _ stairwell shall be pressurized when necessary for sequential ventilation
Evacuation stairs
Fans blowing fresh exterior air into the structure have shown to be _% more efficient than negative pressure vent.
75%
What if negative results are encountered w/PPF?
Discontinue by throttling fans to idle, close stairwell door, & notify IC
Natural tendency of air movement
High pressure area to low pressure area
PPF issued to Hi-Rise Units & select Lad shall be inspected and started at what times?
A. At the beginning of every tour and ran at full RPM weekly at MUD for 5 minutes
B. Daily at the beginning of the 9X6 tour and ran at full RPM weekly at MUD for 5 minutes
C. Daily at the beginning of the 9X6 tour and ran at full RPM weekly at MUD for 15 minutes
D. At the beginning of every tour and ran at full RPM weekly at MUD for 15 minutes
B
Mechanical Vent most correct
A. Use a low exhaust opening, in preference to a high exhaust opening
B. Insure inlet opening double the size of exhaust opening
C. Fans placed 4-6’ from inlet with angle of 70 degrees
D. Both of your 2 fans placed at the inlet opening
D
Exhaust opening- higher is better. Inlet opposite exhaust opening allows fans to push fresh air into structure. Farther back than 4-6’ at 80 degree angle. Exhaust opening Double size of opening fan placed. The more fans the better
As the Off of the 6th Lad responding on a 10-77, you would know which statement is the only correct placement of the Positive Pressure Fans for sequential ventilation?
A: The fan shall be positioned to blow into the attack stairwell and should never be placed in the stairwell.
B: The fan shall be positioned on the exterior of the building with exhaust hoses in place.
C: This ventilation can be carried out floor by floor if smoke or CO contamination occurs on multiple floors starting at the highest point of contamination.
D: The bulkhead (top vent) should be closed in the attack stairwell.
B. 8.1 Note: Placement of the fan for sequential ventilation shall be on the exterior of the building with exhaust hoses in place. The goal of sequential ventilation is to replace the smoke and CO in the building with fresh air.
A. 8.1 After fire extinguishment, the products of combustion can be ventilated vertically through the attack stair. This is accomplished by placing a fan at the base of the evac stairwell, and pressurizing that stairwell.
C. 8.2 This ventilation can be carried out floor by floor if smoke or CO contamination occurs on multiple floors. Start at the lowest point of contamination and work towards the top of the building.
D. 8.2 The bulkhead (top vent) should be opened in the attack stairwell.
