NFPA 1142
STANDARD ON WATER
SUPPLIES FOR SUBURBAN
AND RURAL FIRE FIGHTING
NFPA 1142
WATER SUPPLY
DETERMINING FACTORS
•EXTENT OF EVOLUTIONS
•SIZE OF and TYPE OF STRUCTURE
•CONTENTS
•METHOD OF ATTACK
•EXPOSURES
•RESERVES
NFPA 1142
NFPA 1403: 4.2 Structures and
Facilities
4.2.23
The lead instructor shall determine the rate
and duration of water flow necessary ...,
including the water necessary for control
and extinguishment of the training fire, the
supply necessary for backup lines to protect
personnel, and any water needed to protect
exposures.
NFPA 1142
NFPA 1403: 4.2 Structures and
Facilities
4.2.23.1
The minimum water supply and
delivery for the live fire training
evolutions shall meet the criteria
identified in NFPA 1142, Standard on
Water Supplies for Suburban and Rural
Fire Fighting.
NFPA 1142
Definition: 4.1.5
(1) Exposure Hazard
STRUCTURE WITHIN 50 FEET and
100 SQUARE FEET OR LARGER.
(2) If class 3 or 4 OH, within 50 ft of another building,
it is considered an exposure hazard regardless of
size.
NFPA 1142
Chapter 5
CLASSIFICATION OF OCCUPANCY
HAZARD
WHAT OCCUPANCY TYPE IS THE
MOST LIKELY TO BE USED IN LIVE
FIRE TRAINING?
NFPA 1142
NFPA 1142 5.2.5
Occupancy Hazard Classification 7
5.2.5.1 Light hazard occupancy
Dwellings
NFPA 1142
Classification Of Construction
6.2 .... structures shall be
classified by type of
construction and shall be
assigned a construction
classification number.
NFPA 1142
Classification Of Construction
6.2.1 Type V (Wood Frame)
Construction Classification
Number 1.5
Dwellings
NFPA 1142
Chapter
4
Minimum
Water Supply
=
(TOTAL CUBIC FT) x (CONST CLASS OCCUP 1.5) x ( Exp. Factor 1.5)
(CLASS # 7)
PER 1142 FOR ALL EXPOSURE HAZARDS
MULTIPLY TOTAL BY:
1.5
NFPA 1142
NFPA 1142
4.2 SINGLE STRUCTURES WITHOUT EXPOSURE
HAZARDS
(2000 gal. minimum)
4.3 SINGLE STRUCTURES WITH EXPOSURE
HAZARDS
(3000 gal. minimum)
NFPA 1142
NFPA 1403
50% Reserve
SINGLE STRUCTURES WITHOUT EXPOSURE
HAZARDS
(3000 gal. minimum)
SINGLE STRUCTURES WITH EXPOSURE
HAZARDS
(4500 gal. minimum)
NFPA 1142
Determining Minimum Water
Supplies
4.6
The fire department shall develop the capability to
deliver the amount of water determined in
accordance with Sections 4.2 through 4.5 to the
incident scene at the rate shown in
Table 4.6.1
NFPA 1142
Table 4.6.1
Total Water Required:
Rate Capability:
< 2,500
250
2,500 - 9,999
500
10,000 - 19,999
750
> 20,000
1,000
NFPA 1142
What if the exposure is
larger than the structure
being burned?
Calculate water supply based
on the larger structure
NFPA 1142
Multiple Exposures?
NCFRC Exception
Add .5 for each Exposure
Example:
2
Exposures
1.5
1st Exposure
+ .5
2nd Exposure
2.0
Exposure Factor
NFPA 1142
3 Exposures = 1.5 + .5 + .5 = 2.5
(1)
(2)
(3)
4 Exposures = 1.5 + .5 + .5 + .5 = 3.0
(1)
(2)
(3)
(4)
NFPA 1142
Determining Minimum Water
Supplies
Go back to NFPA 1403: 4.2.23.2
A minimum reserve of additional water in
the amount of 50 percent of the fire flow
demand in 4.2.23.1 shall be available to
handle exposure protection or
unforeseen situations.
NFPA 1142
Practice Time!
See if your calculations are the
same!
(Remember – calculate gable roofs as ½
the height from the attic floor to the ridge
pole)
50’
NFPA 1142
50 x 24, 2 stories with gable roof,
8’ from attic floor to ridgepole
24’
50 X 24 = 1,200 square ft.
Height = 8 + 8 + 4* = 20’
1,200 x 20 = 24,000 cubic ft.
2 story w/gable roof
8’ ceilings
8’ to ridgepole
(Dwelling)
Exp.
OCCUP HAZ CLASS = 7
(divide by 7) 3429 GAL.
Go to Table 4.6.1
CONST CLASS = 1.5
(multiply by 1.5) 5144 GAL.
Table 4.6.1 shows: 500 GPM
1 EXPOSURE HAZARD
(multiply by 1.5) 7715 GAL.
for about 15 minutes. (7715 gal / 500GPM)
Must be capable of flowing 500 GPM
Exposure
50% additional reserve per
NFPA 1403: 11,573 Total Gallons
NFPA 1142
65’ x 30’ = 1,950 square ft
Height = 8’ + 4* = 12 ft.
1,950 x 12’ = 23,400 cubic ft
65’
Exp.
30’
1 story w/gable roof
8’ ceilings
8’ to ridgepole
OCCUP HAZ CLASS = 7
(divide by 7) 3343 GAL.
CONST CLASS = 1.5
(multiply by 1.5) 5014 GAL.
2 EXPOSURE HAZARDS
(multiply 1 + .5 + .5)
Go to Table 4.6.1
Exp.
Dwelling
750 GPM Flow for about 14
minutes (10,029 gal / 750 GPM)
10,029 Gallons
50% additional per
NFPA 1403:
Exposures
15,044 Total Gallons
NFPA 1142
52’ x 44’ = 2,288 square ft
Height = 10’ + 10’ + 10* = 30’
2,288 x 30’ = 68,640 cubic ft
Exp.
52’
44’
OCCUP HAZ CLASS = 7
(divide by 7) 9806 GAL.
CONST CLASS = 1.5
(multiply by 1.5) 14,708 GAL.
3 EXPOSURE HAZARDS
(1.5 + .5 + .5 = 2.5)
36,772 Gallons
Exp.
2 story
w/ mansard roof
10’ ceilings
Go to TableDwelling
4.6.1
Exp.
1000 GPM Flow for about 37
minutes (36,772 gal / 1000 GPM)
Exposures
50% additional per
NFPA 1403:
55,158 Total Gallons
NFPA 1142
Remember!
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•
•
•
•
•
•
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Calculate Square Footage
Calculate Cubic Footage
Occupancy Hazard Class
Construction Class
Exposure factor
Required GPM
Minutes Flow Sustained
1403 Reserve