29 CFR 1910.159: Automatic sprinkler systems
The official text is on the eCFR. Below: how the section is organized, the paragraphs our ASP questions are built on, and free questions to try.
Quoted from the eCFR, current as of 2026-10-14; last amended 2017-01-01.
How 29 CFR 1910.159 is organized
- (a) Scope and application2 paragraphs
- (b) Exemptions1 paragraph
- (c) General requirements—(1) Design19 paragraphs
Paragraphs our practice questions cite most
Counted across the 12 live PassCited questions on this section: our bank, not the real exam.
“(10) Sprinkler spacing. The employer shall assure that sprinklers are spaced to provide a maximum protection area per sprinkler, a minimum of interference to the discharge pattern by building or structural members or building contents and suitable sensitivity to possible fire hazards. The minimum vertical clearance between sprinklers and material below shall be 18 inches (45.7 cm).”
“(9) Sprinkler alarms. On all sprinkler systems having more than twenty (20) sprinklers, the employer shall assure that a local waterflow alarm is provided which sounds an audible signal on the premises upon water flow through the system equal to the flow from a single sprinkler.”
“(2) For automatic sprinkler systems used to meet OSHA requirements and installed prior to the effective date of this standard, compliance with the National Fire Protection Association (NFPA) or the National Board of Fire Underwriters (NBFU) standard in effect at the time of the system's installation will be acceptable as compliance with this section.”
“(b) Exemptions. Automatic sprinkler systems installed in workplaces, but not required by OSHA, are exempt from the requirements of this section.”
“(11) Hydraulically designed systems. The employer shall assure that hydraulically designed automatic sprinkler systems or portions thereof are identified and that the location, number of sprinklers in the hydraulically designed section, and the basis of the design is indicated. Central records may be used in lieu of signs at sprinkler valves provided the records are available for inspection and copying by the Assistant Secretary.”
Free practice questions on 29 CFR 1910.159
Question 1
A maintenance supervisor is replacing several standard sprinklers in one zone of a warehouse after a forklift strike. A pallet of older style sprinklers left from a decommissioned system is on hand. They are approved units and thread onto the existing fittings. The supervisor proposes installing them now to avoid a delay. What must happen before these older style sprinklers can be used in that zone?
Show answer and source
Answer: B. A complete engineering review of the altered part of the system must be done first.
OSHA's sprinkler rule, 29 CFR 1910.159(c)(8)(ii), bars using older style sprinklers to replace standard sprinklers without a complete engineering review of the altered part of the system. Approval and thread fit do not meet this requirement. The waterflow alarm and the 18-inch clearance are separate requirements under 1910.159(c)(9) and (c)(10). Neither one replaces the review.
Answer B rests on
29 CFR 1910.159(c)(8)(ii)(opens ecfr.gov in a new tab)“The employer may not use older style sprinklers to replace standard sprinklers without a complete engineering review of the altered part of the system.”
Question 2
A plant's required wet pipe sprinkler system had its main drain flow test 14 months ago. The inspector's test valve was last opened 18 months ago. No other tests have been done since. A safety professional reviews the records against OSHA's sprinkler maintenance rules. Which statement is correct?
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Answer: C. The main drain flow test is overdue, but the inspector's test valve is not yet due.
OSHA's sprinkler standard requires a main drain flow test on each system annually, so 14 months is overdue. The inspector's test valve must be opened at least every two years, so 18 months is still acceptable. The choices claiming both are overdue, neither is overdue, or that the valve is the late item misstate those intervals.
Answer C rests on
29 CFR 1910.159(c)(2)(opens ecfr.gov in a new tab)“The employer shall assure that a main drain flow test is performed on each system annually. The inspector's test valve shall be opened at least every two years to assure that the sprinkler system operates properly.”
Where it shows up in exam prep
Find out which regulations you'd miss
Other Part 1910 sections
- 29 CFR 1910.1020: Access to employee exposure and medical records
- 29 CFR 1910.1030: Bloodborne pathogens
- 29 CFR 1910.1053: Respirable crystalline silica
- 29 CFR 1910.106: Flammable liquids
- 29 CFR 1910.119: Process safety management of highly hazardous chemicals
- 29 CFR 1910.120: Hazardous waste operations and emergency response
A study aid, not legal advice or an official interpretation. Always check the current eCFR text.