60 seconds of Dry Pipe System Trip Test Results
Dry pipe sprinkler system trip tests may seem straightforward, but there is a misconception that systems must deliver water to the inspector’s test valve within 60 seconds.
To clarify NFPA 25: Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems requirements, let’s review two examples and how to interpret them:
Dry pipe trip test examples
- Example 1. The system has a volume of 600 gallons and also has a quick opening device installed. The original acceptance test water delivery time was 1 minute 30 seconds. The system has been in service for 15 years, and the most recent water delivery time is 1 minute 40 seconds.
- Example 2. The system has a volume of 300 gallons and does not have a quick opening device installed. The original acceptance test water delivery time was 30 seconds. The system has been in service for 6 years, and the most recent water delivery time is 51 seconds.
Given the two examples above, which dry system would be considered a failure based on the requirements of NFPA 25? I will give you a hint; it is not example 1.
Interpreting dry pipe sprinkler system trip test results
Technically, neither system is considered a failure. NFPA 25 does not provide a pass/fail criteria for full flow trip tests of dry pipe systems. The recorded results are for comparison to the original acceptance tests or previous tests if the original tests are not available. This is an important reason for maintaining acceptance test results on the owner’s certificate and the general information sign.
NFPA 25 14.3.1(15) Obstruction Investigation. A 50 percent increase in the time it takes water to travel to the inspector’s test connection from the time the valve trips during a full flow trip test of a dry pipe sprinkler system when compared to the original system acceptance test.
Based on the results: example 1 would require no action, but example 2 would require an obstruction investigation because the water delivery time has increased by 70 percent.
In many cases, example 2 would not be cited because it delivered water in under 60 seconds. However, example 1 would be cited because the water delivery time is greater than 60 seconds … but there is not more than a 50 percent increase in water delivery time, right?
More information on NFPA 25 2017 dry system trip tests:
13.4.5.2.2.2* Every 3 years and whenever the system is altered, the dry pipe valve shall be trip tested with the control valve fully open and the quick-opening device, if provided, in service.
13.4.5.2.5.2 Records of dry pipe valve tripping time and water transit delivery time to the inspector’s test connection shall be maintained for full flow trip tests.
A.4.5.2.2.2 For dry pipe systems that were designed and installed using either a manual demonstration or a computer calculation to simulate multiple openings to predict water delivery time, a full flow trip test from a single inspector’s test connection should have been conducted during the original system acceptance and a full flow trip test from the single inspector’s test should continue to be conducted every 3 years. The system is not required to achieve water delivery to the inspector’s test connection in 60 seconds, but comparison to the water delivery time during the original acceptance will determine if there is a problem with the system.
A.3.3.46 Testing. These tests follow up on the original acceptance test at intervals specified in the appropriate chapter of this standard.
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