Understanding Sprinkler Sampling Procedures

Sprinkler systems are a fundamental part of fire safety, and conducting regular testing is crucial to verify their effectiveness in the case of an emergency. A key aspect of this testing involves various sampling procedures, which are necessary to accurately evaluate the performance and reliability of a system. These procedures are closely tied to the field service testing we covered in our previous blog, where we examined sprinkler testing intervals and how these tests are carried out to verify that sprinkler systems are compliant with NFPA 25. Determining whether your sprinkler system requires replacement or periodic testing is essential for maintaining its effectiveness. Once testing is deemed necessary, it’s crucial to have a thorough understanding of the sampling procedures involved. These procedures can be divided into two phases, each playing a vital role in assuring your sprinkler system is both compliant and operational. In this second segment of our four-part sprinkler testing series, we will explore the key aspects of sprinkler sampling procedures and outline proactive steps you can take to verify your systems comply with NFPA 25 standards.

Phase 1: Pre-Sampling Procedures

The pre-sampling phase consists of all the necessary steps that need to be taken before you can send your sprinklers in for testing. It is important to understand your sprinklers’ testing interval and whether replacement is needed. Once you have hit the 20-, 25- or 50-year mark and do not want to replace your sprinkler system entirely, you are able to send in a sample for testing. However, this does come with some important guidelines and procedures.

As outlined in NFPA 25, section A.5.3.1.1, a visual inspection of the sprinkler system is required before you can test. This floor-level inspection must align with the criteria in NFPA 25, section 5.2.1.1.1, which specifies the conditions under which sprinklers should be replaced. These inspections must be conducted by qualified personnel, whether that is the building owner or an authorized representative. Any sprinkler that shows signs of any of the following will need to be replaced immediately:

• Leakage
• Corrosion detrimental to sprinkler performance
• Physical Damage
• Loss of fluid in the glass bulb heat-responsive element
• Loading detrimental to sprinkler performance
• Paint, other than applied by the sprinkler manufacturer, detrimental to sprinkler performance

These are key signs to look for during your floor-level inspections before submitting sprinklers to an approved laboratory. If any of these issues are identified, the affected sprinklers must be replaced right away, and the remaining sprinklers should be sampled and sent in for testing.

Phase 2: Sampling Procedures

Once you've completed the pre-sampling phase and determined whether your sprinkler systems require testing, it's time to proceed to the sampling procedure phase. These steps are crucial as they allow you to take a proactive role in the sampling process. In the following sections, we’ll outline the five key procedures involved in sampling, confirming your sprinkler system remains both compliant and fully operational.

Define your sample area

A critical part when it comes to sampling your sprinklers, is defining your sample area. The sample area is the section of your building or facility from which you’ll collect the sprinklers for testing. This is an important discussion you should have with the building owner or the responsible party, as it can significantly impact the test results.

For example, if your building has different types of environments, such as a conditioned office space, a laboratory, and an unconditioned warehouse, you may choose to define these as separate sample areas. Testing each area independently helps confirm that if one area has a failure, it doesn’t affect the entire building. This is particularly useful in situations where a sprinkler failure in the unconditioned warehouse would only require replacing the sprinklers in that specific area. However, if the entire building were treated as a single sample area, a failure in the warehouse could lead to replacing sprinklers throughout the entire building.

Selecting the right samples

After completing a thorough floor-level inspection and identifying any damaged sprinklers, the next step is to determine which sprinklers need to be sampled. Once you've selected the sprinklers for sampling, it's important to make sure you're choosing the right ones. According to NFPA 25 guidelines, the sprinklers selected should be random and should not be the best or worst looking ones. Instead, aim to select sprinklers that represent a true cross-section of the system’s overall condition.

Additionally, your sample should include various types of sprinklers, especially if your sample area features different manufacturers or sprinkler mechanisms. For example, if your system includes both fusible link and solder pellet sprinklers, both should be represented in the sample. However, sprinklers of the same type and manufacturer that only differ in their orientation (upright, pendent, sidewall, etc.) can be considered the same type so there’s no need to include one of each orientation in your sample.

Determining the number of samples

The number of sprinklers you send for testing depends on the total number of sprinklers in the area and the types of sprinklers in your system. As a reminder, NFPA 25, section 5.3.1.2, requires that a representative sample consist of at least four sprinklers or 1% of the sprinklers in the area, whichever is greater.

For Example:

• If your sample area has 400 sprinklers or less, send in a minimum of 4 samples.
• If your sample area has 500 sprinklers, send in 5 samples.
• For 600 sprinklers, send in 6 samples.

Note: If your system has multiple types of sprinklers, make sure each type is represented. This might mean sending in more than the minimum required number of sprinklers to ensure that all types are represented.

Sending the samples for testing

Once you have determined your sample area and selected the correct sprinklers and quantities, it is time to send the samples to an approved laboratory for testing. It’s important to understand that this is a destructive test — meaning that the sprinkler will be subjected to conditions that will cause it to break.

For example, the sprinkler may be heated in an oven, causing the glass bulb to break and activate the sprinkler mechanism. Therefore, the samples cannot be returned. Once the laboratory tests your sprinklers, they will provide an analysis of the results, indicating whether the sprinklers pass or fail the test.

Taking Action

The final step in the sampling process is evaluating the test results and determining the next course of action for your sprinkler system. If your sprinkler samples pass, the system may remain in service for a set period before the next round of testing is needed. However, if the samples fail, you may need to replace all sprinklers in the sample area or take corrective measures to address the issues.

Testing is essential for assuring your sprinklers are working properly and that your system meets NFPA 25 fire safety standards. Sampling your system is the first step toward confirming that your building is both safe and compliant. As we continue our sprinkler testing series, we’ll explore more key aspects to help create a safer, more compliant environment for you and your community. Stay tuned for Part 3!