Diagnosing Sprinkler System Problems
Moving beyond normal wear and tear.
NFPA Journal®, September/October 2008
New ground has been broken in the diagnosis of sprinkler system problems, but this remains an area in need of attention. For the first time, the 2008 edition of NFPA 25, Inspection, Testing and Maintenance of Water-Based Fire Protection Systems, has introduced the concept of addressing system deficiencies not explained by normal wear and tear, but it has not yet fully addressed the need for periodic hazard evaluation.
NFPA 25 is used for purposes of system inspection, testing, and maintenance, defined as three separate functions:
“3.3.18 Inspection. A visual examination of a system or portion thereof to verify that it appears to be in operating condition and is free of physical damage.”
“3.3.34 Testing. A procedure used to determine the status of a system as intended by conducting periodic physical checks on water-based fire protection systems such as waterflow tests, fire pump tests, alarm tests and trip tests of dry pipe, deluge, or preaction valves. These tests follow up on the original acceptance test at intervals specified in the appropriate chapter of this standard.”
“3.3.20 Maintenance. In water-based fire protection systems, work performed to keep equipment operable or to make repairs.”
Section 4.1.4 addresses corrections and repairs:
“4.1.4 Corrections and Repairs. The property owner or occupant shall promptly correct or repair deficiencies, damaged parts or impairments found while performing the inspection, test and maintenance requirements of this standard.”
“22.214.171.124 Corrections and repairs shall be performed by qualified maintenance personnel or a qualified contractor.”
A new annex section goes beyond the subject of repairs into the area of diagnosing potential problems:
“A.126.96.36.199 System deficiencies not explained by normal wear and tear, such as hydraulic shock, can often be indicators of system problems and should be investigated by a qualified person or engineer. Failure to address these issues could lead to catastrophic failure.”
The annex goes on to list symptoms of deficiencies not explained by normal wear and tear, including damaged pressure gauges, hangers, valves, wall penetrations, unexplained leakage, and unusual pump vibration or noises.
This section of the standard makes an important distinction: In the area of investigation, it calls for “a qualified person or engineer,” which is different from “qualified maintenance personnel or a qualified contractor.” In effect, the diagnosis of system deficiencies may require knowledge and experience beyond that of a competent sprinkler system inspector, involving product testing, statics and dynamics, strength of materials, hydraulics, and interaction with other building systems.
The issue is not unlike the common confusion between a system inspection and a system hazard evaluation. The purpose of a system inspection, consistent with the above definition, is to ensure that the system equipment is in proper operating order. The inspection does not address design or installation issues that would ultimately predict the ability of the system to address adequately the fire hazard of the occupancy.
Consider, for example, the potential for obstructions to sprinklers. Section 188.8.131.52 only requires that the inspector check for minimum clearance below sprinklers to stock and furnishings, with the annex noting that other obstruction rules “are impractical to enforce under this standard.” NFPA 25 recognizes that other, specific obstruction rules, such as those for early suppression fast-response (ESFR) sprinklers, have changed several times in the various editions of the installation standards. How would an inspector be expected to know all elements of the specific basis of design for a system?
Although NFPA 25 contains regular schedules for the inspection, testing, and maintenance of various system components, it contains no regular interval or trigger for a hazard evaluation comparing the potential fire severity to the system’s capability. Where changes to the occupancy, fire hazard, water supply, storage commodity, storage arrangement, building modification, or some other condition that affects system installation criteria take place, the owner is obligated under Section 4.1.6 to take appropriate steps to evaluate system adequacy “such as contacting a qualified contractor, consultant or engineer....”
Unfortunately, subtle or gradual changes in the fire hazard of building contents or interior arrangements often take place undetected. As with unexplained system deficiencies, the type of person best able to evaluate system capability is rarely the same type of person who conducts system inspections, since the hazard evaluation requires a greater knowledge of applicable NFPA standards and other aspects of system design.
As the NFPA 25 Technical Committee prepares the next edition, it will receive a proposal that a hazard evaluation form be included parallel to the sample system inspection forms found in past editions. Even without a specific trigger or time interval, such a form would clarify the types of issues not addressed in a typical system inspection.
Russ Fleming, P.E., is the executive vice-president of the National Fire Sprinkler Association and a member of the NFPA Technical Correlating Committee on Automatic Sprinklers.