HomeMy WebLinkAbout405.018 - Sprinkler Piping Under One Inch in DiameterEffective Date: March 1999 Justin H. Beal, Fire Prevention Engineer
Current Revision Date: 1/31/2025 Section 405.018
Next Revision (1) Date: 1/31/2028 Page 1 of 3
Fresno City Fire Department
400 Prevention Manual
SECTION 405.018 SPRINKLER PIPING LESS THAN ONE INCH IN DIAMETER
PURPOSE
The purpose of this policy is to clarify the Fresno Fire Department’s (FFD or
Department) requirements related to existing automatic fire sprinkler system piping
which is less than one (1”) inch in diameter.
APPLICATION
This policy applies to all fire automatic sprinkler systems within the City of Fresno
(COF) and contract service areas and includes both required and voluntary systems.
This policy does not include automatic fire sprinkler systems installed in one-and two
-family dwelling units, or where automatic fire sprinkler systems were installed per the
requirements of National Fire Protection Association (NFPA) Standard 13D - Standard
for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and
Manufactured Homes.
OPERATIONAL POLICY
Based upon the need for uniformity in application across the Department’s diverse
service delivery area, and after careful deliberation, the Department has determined
that during every automatic fire sprinkler system 5-year inspection where three-fourths
(3/4”) inch piping is installed in the system, the following requirements shall apply:
1. If the three-fourths (3/4”) inch pipe is at the highest elevation of an
upward sloping branch line, the contractor must remove and inspect one
(1) of every ten (10) sprinkler system branch lines. If corrosion or other
concerns are noted in more than three (3) pipe segments, all three-
fourths (3/4) inch pipe in the system must be removed and inspected.
2. If the three-fourths (3/4”) inch pipe is at the lower elevation of an upward
sloping branch line, or on a horizontal branch line, the contractor must
remove and inspect one (1) of every four (4) branch lines. If corrosion or
other concerns are noted in more than three (3) pipe segments, all three-
fourths (3/4) inch pipe must be removed and inspected.
3. At least three (3) drops and/or tailbacks, on separate sprinkler branch
lines, must be removed and inspected for corrosion and sediment. If
either corrosion or sediment is located, all three-fourths (3/4) inch pipe
must be removed and inspected.
Effective Date: March 1999 Justin H. Beal, Fire Prevention Engineer
Current Revision Date: 1/31/2025 Section 405.018
Next Revision (1) Date: 1/31/2028 Page 2 of 3
4. Piping which is found to have its cross-sectional flow area reduced by a
significant amount as determined by the Fire Marshal (or designee) shall
be replaced.
If more than half of the pipe inspected is found to have its cross- sectional flow area
reduced by a significant amount as determined by the Fire Marshal (or designee) all
three-fourths (3/4”) inch pipe, related fittings, sprinkler heads, etc. must be replaced
(with a permit) with one inch (1”) pipe.
OPERATIONAL GUIDELINE
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PROCESS
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INFORMATION
As noted in the California Fire Code (CFC), the fire code official has the authority to
formulate policies they deem necessary based upon local conditions related to all fire
sprinkler systems and equipment.
At one time, three-fourths (3/4”) inch diameter piping was considered acceptable to
serve a single, fire sprinkler head in an automatic fire sprinkler system. Although this
smaller diameter pipe loses three (3) pounds of pressure per square inch (psi) over
ten (10’) feet of run of pipe for a light hazard occupancy application (0.76 psi for 1-
inch pipe), there is no need to replace three-fourths (3/4”) inch piping that has not had
its cross-sectional flow area reduced.
After an automatic fire sprinkler system reaches fifty (50) years of age (and coinciding
with the systems normal 5-year inspection), all three-fourths (3/4) inch sprinkler pipe
within an automatic fire sprinkler system must be detached and its interior inspected
to determine if its cross-sectional flow area has been reduced by corrosion, scale, etc.
DEFINITIONS
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Effective Date: March 1999 Justin H. Beal, Fire Prevention Engineer
Current Revision Date: 1/31/2025 Section 405.018
Next Revision (1) Date: 1/31/2028 Page 3 of 3
CROSS-REFERENCES
National Fire Protection Association (NFPA) Standard 13D, Standard for the
Installation of Sprinkler Systems in One-and Two-Family Dwellings and
Manufactured Homes, Currently adopted edition
California Fire Code, Currently adopted edition.