At the start of relay operation, all pumpers should be set to pump __ to the pumper at the fire
150 psi
Incoming pressure to the next pumper in the relay should never drop below __
20 psi
Excessively long relays, those exceeding __ may require relaying operations
1000 ft (up to 2000 ft max)
Advantages of forward lay
- Company is self sufficient in terms of water supply
- Co. is free to take up any position
- Later arriving units may drop off crew
- A lg hoseline or masterstream may be used immediately
Disadvantages of forward lay
- Slight delay when pumper stops to hook up to hydrant
- Temp loss of firefighter to charge supply line
- Supply lines being laid may hinder access of ladder company
Advantage of Large Diameter Hose (LDH)
- Increase in flow area
- Reduction in friction loss
- Increased productivity
Factors in ascertaining what rescue operations are needed:
- Extent of fire
- Building size
- Building age
- Occupancy
- Apparant population
Direct attack
An attack in which a solid or straight hose stream is used to deliver water directly onto the base of the fire
Indirect attack
An attack in which a solid, straight, or narrow fog stream is used to direct water at the ceiling to cool superheated gases in the upper levels of the room
Disadvantage: Water-to-steam expansion ratio is capable of causing serious burns to firefighter and victims
Most common smooth bore tips sizes for master steam appliances
- 1 3/8 (500 gpm)
- 1 1/2 (600 gpm)
- 1 3/4 (800 gpm)
- 2” (1000)
Note: These should be operated at 80 psi
Recommended pressure when supplying sprinkler systems
150 psi
Conduction
Travel of heat through a solid body
Convection
Travel of heat through the motion of heated matter; smoke, hot air, heated gases
Note: Convection is the main reason for ventilation requirements
Radiation
Travel of heat through space, no material substance required
- Unaffected by wind
- Unless blocked, radiated evenly in all directions
- Greatest cause of exposure fires
- Cannot ignore windward side of building
Note: Proper ventilation does little to help against radiant heat. Radiant heat must be counteracted with adequate amounts of water at the seat of the fire
The only way to protect exposures from radiant heat is to cool them with water
4 types of spray nozzles
- Basic spray
- Constant gallonage
- Constant pressure (Automatic)
- Select gallonage
Backup lines for:
Two 1 3/4” lines
One 2 1/2” line
Two 1 3/4” lines = One 2 1/2” line
One 2 1/2 line = One 2 1/2” line
Note: If 2 1/2” hoselines are used for initial attack, backup lines should be 2 1/2” lines with larger tips. If the lines have spray nozzles, backups should be equipped with smooth bore tips
Pump operators should maintain a residual pressure of __ psi?
20 psi
Note: The residual pressure should not be allowed to drop below 10 psi, except under extreme circumstances
Classes of standpipe systems - I, II, II
Class I - Provide 2 1/2” hose connections for full scale firefighting. Intended for use by fire dept, not building occupants
Class II - Provide 1 1/2” connections for first-aid firefighting. Intended for use by building occupants
Class III - Combo of Class I and Class II
Note: Class I and III systems must provide 100 psi residual pressure at top-most hose connections w/ a minimum flow of 250 gpm
Class II systems must deliver 100 gmp for 30 minutes. It also must maintain a residual pressure of 65 psi at most remote connection while flowing 100 gpm
The attack hose is designed for pressures up to __
275 psi
A 2 1/2” supply line should not be used to deliver much more than __
350 gpm
A pumper at hydrant should initially begin pumping to the unit at the fire at __
100 psi
Basement fires
- An aggressive interior attack should be made from the unburned side
- In most cases the fire, heat, and smoke are venting out in the proper directions (the burned side)
- If fire is burning up stairways, an attack line must be positioned to protect stairway
- Ventilation is a key elemen in controlling the fire
- A fire in the basement is much more dangerous to occupants than a fire on an upper floor
NFPA 1901 requires a minimum of __ ft of 1 1/2”, 1 3/4”, or 2” hose to be carried on a pumper apparatus
400 ft
FDC’s
- Most are provided with one 2 1/2” inlet for each 250 gpm of design flow rate
- It is preferable to use 4” or larger piping for connecting the FDC to the system mains
- For siamese, 1st line should be connected to the left intake
