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Standpipe Hydrostatic Testing

Standpipe Hydrostatic Testing

Theory vs. Practice

Every industry has areas where theory and practice just don’t quite meet. The fire protection industry is no exception. If your firm is responsible for performing inspections on water-based fire protection systems, then you can relate to that statement. Honestly, trying to complete the various code inspections on a standpipe system can often times be challenging within certain jobsite conditions. Take for example, the five-year hydrostatic testing requirement. After reading the 2014 edition of NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, (section 6.3.2.1) we learn that “hydrostatic tests of not less than 200 psi pressure for two hours, or at 50 psi in excess of the maximum pressure, where maximum pressure is in excess of 150 psi, shall be conducted every five years on manual standpipe systems and semiautomatic dry standpipe systems, including piping in the fire department connection.” Well, that sounds simple enough, right? Yet, we still see and hear so much confusion in the industry surrounding this particular test.

So, what do we know for certain about this requirement? We are told the test has to be performed every five years; we have to achieve at least 200 psi of pressure; and we have to keep it on the system for two hours. We are also told in section 6.3.2.2 that we have to measure this pressure “at the low elevation point of the individual system or zone being tested.” If that’s all there is to the test then it shouldn’t be difficult to perform, but it’s often riddled with confusion and inaccurate results. Truthfully, the difficulty lies in multiple areas, but for this article we’ll mainly focus on the area of the test with respect to the wording from the standard, “including piping in the fire department connection.”

Obviously, the purpose of performing the inspection is to notate what is seen and to document the current operational status of the system so that it can be properly maintained. In most cases the results correlate into a quantitative pass or fail criteria. So, wouldn’t it be nice to understand where a component passes and what constitutes a failure? Section 3.3.20 of NFPA 25 defines a hydrostatic test as being performed to “verify system integrity and leak rates.” We know from section 6.3.2.2 that we are supposed to check the pressure drop since we’re told to measure it at the “low elevation point.” Unfortunately, we are not given any guidance beyond that. The acceptance test criterion in NFPA 14, Standard for the Installation of Standpipe and Hose Systems, uses similar text, whereas NFPA 13, Standard for the Installation of Sprinkler Systems, states that it “shall maintain that pressure without loss.” The only criteria provided is in section 6.3.2.2.1: “The inside standpipe piping shall show no leakage.” That would seem to indicate that any drop in pressure is not allowed; however, before we make that assumption, A.6.3.2.1 states, “Minimum leakage existing only under test pressure is not cause for repair.” So, we are left with the understanding that some leakage is acceptable but without the quantitative value to define it.

In addition, section 6.3.2.2.1 quoted above actually has two issues worth discussing. Firstly, 6.3.2.2.1 states “shall show no leakage.” This tells us that we have to walk down the system looking for visible signs of leakage. As discussed in the annex, the concern is more about the system retaining its integrity during fire conditions and less about a minor amount of water escaping the pipe. So how much is too much? Well, intuition would indicate any leaking is going to cause concerns with the owner, and certainly the larger the leakage, the larger the concern for all those involved.

The second issue is the use of the reference to the “inside piping.” What does that mean since all piping is typically inside the footprint of the building, and the building code does not require walls for a structure to be a building? So does it mean inside the heated boundary? After all, a minor leak inside a parking garage causes less concern than inside an office. In the event there is ever a failure of the piping integrity, your judgment call allowing some leaking will be aggressively challenged. If the intent of the standard is to depict, through the inspection, the integrity of the piping for use by the fire department, then it really shouldn’t matter from the standpoint of NFPA where the leak is occurring. If the integrity of the pipe is poor, the potential to save the structure or the lives within is reduced. I wouldn’t be comfortable presuming that the owner of an empty warehouse thinks any less of his facility than the owner of a hotel; both spent their time and resources to create the structure.

Now, let’s move on to the issue of what must be tested. The first step is to identify the types of standpipes that exist. After all, how can it be tested if it cannot be recognized? I conducted a small poll, not scientific in nature but interesting nonetheless, where I questioned various field techs and engineers about standpipes. In speaking with them, most were able to recall the automatic and manual styles. Fewer were able to identify that there are manual wet in addition to manual dry, and fewer still were able to recall the existence of the semiautomatic dry standpipe. The combined standpipe (either automatic or manual attached to the sprinkler system) was something most knew about, but was not in the thought process until it was mentioned. Although not part of this article, it is interesting to note that some confusion seemed to stem from the idea that most people thought “automatic” standpipes were those that automatically had water going to them without the need for human intervention, when in fact, a standpipe is automatic when the water supply is “capable of supplying the system demand … with no action other than opening a hose valve.” I mention that just to iterate the number of paths of discussion that standpipes can foster.

So, the hurdle is to differentiate between the types of standpipes and then understand that stand alone manual wet standpipes, manual dry standpipes, and semiautomatic dry standpipes are all that apply the hydrostatic testing requirement. “Manual wet standpipes that are part of a combined sprinkler/standpipe system,” automatic wet standpipe systems, and automatic dry standpipe systems do not have to be tested under the hydrostatic requirement. The handbook would further explain the reasoning to be that these three are “supervised,” for lack of a better word, as they contain either water or air on them at all times to indicate a leak. I must confess that building owners and managers are likely to react if water is leaking, but suspect few would respond to having their compressor running more than usual unless someone complains about the noise.

The standard appears to specifically instruct the inspector to focus on three of the six types of standpipes. Or does it? What about that part of the standard that we are focused on for this article – the piping in the fire department connection (FDC)? That part of the piping in those three systems is not subjected to the continued operating pressures that exclude the systems themselves. Is it the intent to not test that portion of the piping on those three standpipes that are otherwise excluded in the standard? Apparently, the answer is yes; it is specific to just those three identified. That clause of the sentence in the code reference is not meant to be a global requirement for all systems, but is a reminder that the portion of pipe between the check valve and the FDC must also be checked. It is, however, a good question as to why we aren’t required to test this portion of piping in all system types. The potential for this section of piping to have integrity concerns reaches across all 6 types of standpipes, not just those three. To add confusion, section 6.3.2.1 may not intend for that portion of the standard to be global, but section 13.7.4 surely does.  It plainly reads, “The piping from the fire department connection to the fire department check valve shall be hydrostatically tested at 150 psi (10 bar) for 2 hours at least once every 5 years.”  So, a literal interpretation lands us back to testing all six types of standpipes from the check valve to the FDC.

Let’s assume for the sake of this article that the Authority Having Jurisdiction (AHJ) elected to have the FDC piping hydrostatically tested in all six types of standpipe systems. Since three of them are most likely combined with an automatic sprinkler system, how exactly does one go about testing that piping? In cases where the piping is all exposed and connected to a wall FDC, the procedure can be completed with a few modifications to the piping. Remove the Siamese connection, replace it with a cap that has been tapped with a gauge and test rig connection, plug the ball drip, and either blank off the check valve or spin it around in place in the piping. Remember, working with the check valve requires shutting down the sprinkler system on three of the six types of standpipes, so the facility with those types of standpipes will be without fire protection for an indefinite amount of time. That procedure takes us one more step down an unintended path. Is it the intent of the standard to require disassembly of the piping? If so, what testing procedures would need to be performed after reassembly in order to meet the purpose of the hydrostatic test which is to confirm the integrity of the piping that you just disassembled? The reasonable answer is to use the system working pressure as identified in the Tables on Summary of Component Action Requirements.

Taking the same example as above, but moving the FDC piping into a wall cavity or soffit significantly increases the difficulty in performing the test. Although the procedures are the same for anything exposed, some of the modifications that need to be made to the piping may not be accessible. The check valve and the ball drip may be inside the wall. In that case, is it the intent of the standard to pump up the entire standpipe system that was excluded in order to test the piping to the FDC? If not, what is expected of the inspection team with respect to dismantling walls and soffits? Remember, this discussion also includes the piping to the FDC in the three systems that are most likely tied to sprinkler systems. Minimal leakage in these three systems becomes an issue for two reasons. Firstly, if the entire system is pumped up and the test gauge indicates a leak, how would inspectors make an assessment of whether the leakage is from the sprinkler system or the standpipe, since the FDC piping is not exposed? Secondly, NFPA 24, Standard for the Installation of Private Fire Service Mains and Their Appurtenances, does not speak to a value of leakage acceptable to above ground piping; only underground piping is given a quantitative measure as we’ll see in the next paragraph.

Now, let’s turn our attention to yard FDCs and the associated underground piping and appurtenances. Herein lies another dimension of difficulty with this requirement. What is the intent of the test if not to “ascertain whether the system retains its integrity under fire conditions” as stated in A.6.3.2.1? NFPA 24 quantifies acceptable leakage for underground piping as +/- 5 psi over two hours during acceptance testing. Is it the intent of the committee to use that value as the definition of “minimal leakage” for existing underground piping in NFPA 25? If so, notice the same reference says that minimal leakage “under test pressures” is not cause for repair. So, if the leakage exceeds what is acceptable to the standard once defined, what course of action is reasonable to remedy the situation since the leak could be anywhere along the underground from the ball drip, to the check valve, couplings, or piping itself?

As we have indicated, the phrase “including piping in the fire department connection” creates numerous questions and testing difficulties for an inspection team. Couple these questions with the additional issues of determining differences in standpipe types, system demands, and cross-referencing standards, and it isn’t a stretch to see why standpipes can be so difficult. This article is intended to highlight how confusion may lead to untested pieces of equipment or incorrect testing results. Additionally, a lack of understanding by inspection teams could lead to misdiagnosed problems and incorrect solutions offered to the customer at an unnecessary expense that may not resolve the true existing issues. As we can see from this article, hydrostatic standpipe testing is more involved than just pumping up some piping, letting it sit for two hours, and then reading a gauge. Like most codes, NFPA 25 is no different. Teams of qualified people deliberate in great length over these issues; there is no easy answer that covers all situations. The inspector will always have to use some educated judgments in order to perform the quality job expected. Through continual communication, education, and application, we can all come to understand the intent of the code and have a clearer vision for providing a safe environment in which to work, play, and relax.

ABOUT THE AUTHOR: Howard Clay is a native of Virginia and is employed by VSC Fire & Security, Inc. in its Inspection Division. Clay attended  college at Hampden-Sydney where he received his B.A. in managerial economics. He is NICET certified in water-based fire protection systems, fire alarm systems, and fire alarm inspections and testing. Clay holds state backflow prevention testing licenses in both Virginia and North Carolina and carries the FS-IT-C inspection and testing certification in North Carolina. He has authored articles for magazines of local organizations, and has been asked to speak to local businesses, fire departments, and community associations to help them better understand fire protection. Clay is a member of NAFI and IAAI. He can be reached at hgclay@vscfs.com.

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