By Jocelyn Sarrantonio, PE | Technical Director, MeyerFire
 
Think State of the Union, but today I’m going to talk about the State of ESS in Fire Protection. So without further ado, members of the community, today I have the privilege and honor of discussing battery energy storage systems. Please clap. [Applause Please]

Just kidding, but today I wanted to talk about where we are as a fire protection community with regards to the response to the widescale adoption of battery energy storage systems (BESS) practically everywhere.
 
THERMAL RUNAWAY
If you didn’t take my Introduction to ESS course (shameless plug for our recent course, Introduction to Energy Storage Systems), the primary risk that comes with BESS, particularly lithium-ion batteries, is their susceptibility to thermal runaway.

Thermal runaway is a process resulting from a battery failure, where cells inside a battery undergo a rapid temperature increase and vent flammable gases, creating an explosion risk.
​
The risk is proportional to the quantity of batteries in an installation, so you can imagine if we’re not even allowed to have lithium-ion batteries in our checked bags on airplanes, then enormous utility installations pose a substantially higher risk. 

The risk has been a part of our lives for years, so what are we learning about ESS?
 
#1 THE FIRE RISK CAN BE LONG-LASTING.
It can take large volumes of water to sufficiently extinguish and cool fires involving ESS, and due to the stranded energy in battery cells, re-ignition is a risk.

Even battery cells that are not plugged into anything can still undergo thermal runaway, if they are abused.

Emergency responders typically use thermal detectors to find any hot spots after a fire is extinguished, but it is critical to continue monitoring for longer than you’d think after a battery fire. Re-ignition can happen months after the fire! That’s long after the emergency responders have left, so there's a need to develop a protocol to monitor and prevent re-ignition.
 
#2 REGULATION OF E-SCOOTERS, E-BIKES & OTHER MICROMOBILITY DEVICES
In large cities where space is hard to come by and small lithium-ion batteries are everywhere, tighter regulation of micromobility devices is coming.

In New York City, for example, the market has been flooded with low-cost and unsafe products, partially due to the rise of food delivery apps.

The delivery workforce generally earns low wages, and there is no accountability from the app companies on the micromobility devices used. So the workforce is not motivated to purchase quality products, and the result is low-quality batteries being charged inside densely populated buildings.  
 
#3 SHIFTING PUBLIC PERCEPTION
Public perception may start to shift.

We’ve seen the videos of battery fires that include large plumes of smoke, and it’s hard not to imagine how local residents are faring.

Public pushback about BESS projects has increased following recent fire incidents, and the path forward likely includes educating the public to ease their concerns.

Even though the public directly benefits from lower electricity costs or stability of the utility grid, people are not willing to sacrifice safety and negatively impact their community. I’m not sure what that looks like, but it does seem like with any large project, developers have a responsibility to educate the people who are negatively impacted when there is an emergency situation.

If you want to build in someone’s backyard, you’ve got to convince them that what you’re doing is safe, and is a benefit to them.

Maybe that means highlighting training of your staff, the safety of the equipment you’re buying, or investing in local emergency responder equipment.

CONSUMER SAFETY
On the face of it, BESS safety is not just an area of concern for us as fire protection engineers, but as consumers as well.

Lithium-ion batteries are in our cellphones, laptops, electric vehicles, solar panels, and e-bikes. It’s important to note that when we talk about energy storage systems, the IFC and NFPA 855 have a threshold of 20 kWh where these requirements kick in.

For reference and speaking in rough orders of magnitude, a laptop battery might be 0.1 kWh, a phone might be 0.015 kWh, an electric scooter may be 1.5 kWh, EV’s may be up to 100 kWh, but a large Tesla Megapack that would be used in a utility grid installation is up to 4000 kWh, or 4 MWh. 

The risk of thermal runaway exists in all of these products, but the impact is greater as the capacities increase. 

As a consumer, if it is an option you should always buy products that have a mark from a nationally recognized testing laboratory (NRTL). What does that mean? Without getting too far into the weeds, there are several organizations, the most prominent one being UL, that test consumer electronics including TV’s, computers, and even Christmas tree lights.

When a product “bears the UL mark” it means it went through rigorous testing and complies with UL’s safety standards.

​That’s not saying there is no risk, but when we’re talking about a product which carries some inherent risk already, having a genuine product that complies with some standard of safety is even more important. 

It may be tempting to buy the cheapest version of a product, but using non-certified products, or even worse, fake products, can increase the potential risk for fire. This is because those products haven’t been tested to safety standards and they do not necessarily meet those higher quality and safety thresholds. 

You should also follow all manufacturers’ guidance when it comes to temperature control, clearances, ventilation, and where and how to charge devices.

We never want to charge these devices where they will block access to an exit.

Thinking about where people who drive e-scooters might live, it’s probably in a densely occupied apartment structure, and where they may charge their scooter, it’s probably by a door. Many apartments and condos only have one common path of travel, so if there’s a problem it may block the only exit and now a bad situation is worse. 

TRENDS IN INDUSTRY RESPONSE
Some of the trends the industry is seeing come in the form of alternate electrolyte recipes, methods of early detection, and more large-scale fire testing for extinguishing agents. 

First, if lithium-ion batteries are the problem, why don’t we just use different batteries? 

The reason this is even a challenge is that the industry quickly adopted lithium-ion batteries because they are lighter than their historical predecessor, lead-acid batteries. They also have a higher power density, so they can either take up a smaller footprint for the same capacity or get a higher capacity with the same footprint. 

It’s not a perfect analogy, but I think this is akin to the fire protection industry’s history halon as a fire extinguishing agent. 

Halon is a gaseous fire suppression agent that is quite effective, but then we learned how bad it was for the environment, so the industry shifted to other solutions. These other solutions may not be as effective as halon, but they sure outweigh halon’s major disadvantage. 

Similarly, the strategy here is to find other battery chemistries that may not be as inexpensive or energy-dense as lithium-ion, but that outweigh lithium-ion’s major disadvantage. 

Another strategy for the industry is smarter products, which can detect thermal runaway earlier, leaving more time for response. 

I’m keeping a discerning eye out for new products that include more sensitive gas detection, thermal imaging, or other sensors that will help us design more robust systems that mitigate explosion risk. 

Lastly is more large-scale fire test data for extinguishing agents. The code opens the door for alternative extinguishing agents, but I have yet to see good large-scale fire test data for these non-water based agents. There may be a reason for that, if they are ineffective, but so much of our design criteria is based on testing, so I’m looking forward to more data to help us validate design criteria. 

CODE DEVELOPMENT
As you probably are aware, the codes are doing their best to keep pace with the risks, in a reasonable timeline. 
​
The IFC has been revised extensively since 2018 to integrate ESS requirements, and the latest 2024 Edition brings it largely in agreement with the 2023 version of NFPA 855. That standard is currently undergoing its normal revision cycle, with a new edition set to be published in 2026.

It is expected that the 2026 Edition will include additional large-scale fire testing requirements beyond the current UL9540A testing and further development of the Hazard Mitigation Analysis (HMA) procedures.  

With each jurisdiction’s unique adoption of its building and fire codes, there is an opportunity for further amendment of these standards.

It is critical to verify if a jurisdiction has any amendments to the generic code language for ESS and to verify if there are any special permitting procedures for ESS. My next course, coming this quarter, will be a review of the major code requirements for ESS.
 
PROBLEMS THAT REMAIN
It seems that the world is not going to soon give up on the use of lithium-ion batteries in BESS installations, so the toughest challenge that remains is how to deal with the explosion risk.

The tools we have at our disposal, NFPA 68 & 69, were not developed with BESS in mind, but can be part of a layered approach to addressing the explosion risk.

Since we are a prescriptive code-driven industry (in North America at least), we look for guidance on how to design these systems or how to perform these evaluations from the codes & standards themselves. I’m really looking forward to any new guidance in these documents to help give us consensus on how to approach the risk.
 
BEST PRACTICES: SO WHAT DO I DO?
If you are a fire protection engineer (or anyone) involved in an ESS installation, the basic process is as follows:

• EDUCATE: Educate yourself on how you may see ESS in your work.
  
  
• PRODUCT DATA: Gather the data. You will need product data for the ESS and the associated UL9540A test report.
  
  This is the fundamental information you will need to design the system spacing, ventilation, and associated fire protection systems.
  
  
• DEFLAGRATION OR EXPLOSION CONTROL: Evaluate the need for deflagration or explosion control. 
  
  This can have major impact on a design, depending on where the ESS is intended to be installed. Identifying where pressure-relief vents or exhaust ductwork can be routed is key.
  
  
• ENGINEERED SYSTEM INTERFACES: What systems are available that can interface with the BESS?
  
  Understanding the battery monitoring system to determine if information can be used for emergency control functions.
  
  
• COUNSEL OWNERS ON THEIR RESPONSIBILITIES: Many jurisdictions are focusing on the commissioning plans, yes, but also decommissioning plans.
  
  What is the life cycle of these batteries, and how will they be disposed of safely once they have reached their useful life?
  
  Because of the unique hazard BESS can have with stranded energy, you can’t just stack old equipment in a storage room and deal with it later. IFC 2024 also has a new requirement for a fire safety and evacuation plan to be included with the BESS construction documents.
  
  As fire protection engineers, we need to do our best to make owners aware of their increased responsibilities.
  
  

WHAT’S NEXT?
There’s quite a bit to keep up with. Many of us in this space are watching the development unfold. Deployments will only increase as utility grids move toward lower reliance on fossil fuels. Monitoring changes in codes, battery chemistries, and expectations of the public, owners, and AHJs will be needed to build trust and achieve reasonably safe outcomes.  Staying current and educated is our challenge today. Rigorous testing and proactive stakeholder engagement will be important as we all move forward to safer energy storage systems.

So in conclusion, the State of our Union is strong!

​Thanks for reading, until next time, stay safe, and always check your local jurisdiction’s amendments!

Last week, we posted results on what sprinkler contractors need as part of a set of biddable construction documents.

One of the top needs that sprinkler contractors expressed was whether the owner had any insurance-driven criteria that applied to the project.

THE SURPRISE
This likely isn't a surprise if you've encountered it on a job: a building is designed, bid specs are applied, bids are collected, the contract is awarded, sprinkler shop drawings are created and submitted, and then out of the blue [BOOM!], a review comes in from FM Global.

FM Global? Did someone know that this was an FM Global job?

No discredit to the FM Global team whatsoever - they do an excellent job in establishing a higher level of excellence and have propelled our industry for years - but shouldn't we all have known that FM would be a part of the project from the beginning?

That answer, of course, is yes.

CHALLENGES WITH INSURER-DRIVEN CRITERIA
It can be tough to grapple with if you've been on a project where that's been a surprise. It can also put a building owner in a difficult position of mediating what their insurer wants them to provide against the increased cost of doing so via change order.

As we've discussed, delegated design is one key area where a consultant provides tremendous value in coordinating and pre-planning these asks well before bid day, which would create a smoother project experience. Instead, missing or ignoring insurance criteria altogether can set the project back in schedule and cost.

From the consultant's side - it's not always easy to get a straight answer from a building owner. 

VARIABILITY AMONG BUILDING OWNERS
Big developers or large corporate clients are often very informed on their design standards; they may even have a complete set of standards themselves ready to distribute.

Smaller or first-time building owners are often less likely to carry insurance criteria that stipulate much in terms of fire protection above code minimum. 

But what about the projects in between? 

What about the corporate client building in the area for the first time? The regional grocery chain? The distribution center? Mid to large retailers? Restaurants? Healthcare? Manufacturing? Hotels?

Anything in this range could carry insurance that mandates a standard above NFPA 13 in certain areas, including critical ones like sprinkler design criteria.

Just because an insurance company isn't FM Global doesn't mean that FM Global Standards don't apply; many other carriers could still follow FM Global criteria or even have a more comprehensive program like XL GAPs (or something similar).

​
BEST PRACTICES FOR GETTING THE INSURANCE QUESTION ANSWERED
What I'm most curious about is what has been your most successful process for getting this information from a building owner.

As a consultant, I had my best luck when we'd have a design meeting, and the owner or owner's representative was in the room, and I could ask directly about any insurance mandates above code minimum.

The line I used often sounded like, "Do you carry any requirements or standards above code minimum, like FM Global?"

If the owner or owner's representative was familiar with FM Global, there'd usually be a quick yes and they could confirm fairly quickly.

Honestly, all other cases would get a blank stare. I'd explain that the insurance criteria above the code were not the norm but that we'd want to incorporate it if there were any that applied.

In most cases, this was enough information to work from, but I never liked the inexact nature of going by a mostly uninformed answer. I found it to at least elicit a response, unlike emails, which tended to never get returned, but still - there's got to be a better way.

THE BIGGER QUESTION: WHAT WORKS BEST FOR YOU?
From last week, we know that insurance criteria are a major factor in determining what should be in the bid documents.

So my question to the consultants here is: What have you found to be the best approach to getting this information from an owner?

What method has worked to (1) actually get a response from the right person and (2) get a response that's usually accurate?

Let us know in the comments here. I have my lame approach but I'd much rather collaborate and share ideas on what works so that, as a whole, we can do a better job of creating a quality set of bid documents.


Thanks for continuing to advocate for the industry. Hope you have a great rest of your week!

- Joe

While you're here, we've had great discussions on tackling challenges with bid specifications. I'm very encouraged by the response and I'd like to move things forward with drafting an open, easy-to-digest fire sprinkler specification.

My next question for you is - in an ideal, simple, concise fire sprinkler specification - what do you want to see addressed?

If you're bidding on a job - what is it that you want to see adequately addressed in the specification?

Allowable types of pipe? Types of sprinklers? Use of flexible drops, or other fittings? System types?

What is it that you look for that is can't miss in a quality fire sprinkler specification?

​When you conduct a hydrant flow test, how precise is your resulting measurement?
 
Let’s say a flow test summary shows 82 psi static, 54 psi residual at 956 gpm.
 
Is it really 956 gpm? 

Well, no, of course – but 956 is the best resulting estimate of the flow test with the information and measurements we have at hand. It’s where the dial best predicts.
 
But how precise is that measurement, really?
 
Are we certain that it’s 956 gpm and not 957 gpm, or 960 gpm, or 1,000 gpm?
 
Now of course, a hydrant flow test is a point-in-time measurement. It’s not representative of daily fluctuation or seasonal fluctuation.
 
Let’s save that discussion for another time. What I’m really interested in is when we take a flow test or run a pump test, how accurate are our results, really?
 
SIGNIFICANT DIGITS
The concept of significant digits is one simple way avoid suggesting a higher level of precision than a measurement justifies.
 
In other words, if our flow test results said 956.21 gpm, we’re suggesting, based on the decimal placement that we actually know that the value is not 956.4 gpm; it’s instead between 956.2 and 956.3. That’s a level of precision that is suggested by significant digits.
 
Technically, if we had a pitot gauge reading of 9 psi during a flow test, then we would have one significant digit.
 
Using one significant digit is very problematic in flow test results.

​If you don’t think that’s a high-stakes proposition, then I’d invite you to wrap up final acceptance testing on a federal project with every stakeholder present and watching. It can be high stakes.
 
Perhaps the more appropriate way to understand precision is by doing error propagation on this conversion.
 
Error propagation is a sore point for me, as I pretty much failed every physics lab in college that required it. Time to shed those demons.
 
If you’re not into math, skip ahead to the summary to see where I ended up.
 
I want to show my work here as I haven’t seen this done and I’m very much for transparency and getting feedback, especially when I venture a little beyond my own fenceposts.
 
ERROR PROPAGATION FOR FLOW TEST CONVERSION
Error propagation is a fancy way to describe the reliability of the resulting calculation.
 
How precise is the result?
 
That’s what we want to know – and knowing so can help us make more informed decisions in our assessments. 

A formula with multiple variables, where each have their own uncertainty, the overall uncertainty depends upon how each variable affects the final result.
 
In other words – if I’m not exactly sure about the numbers I’m putting in, how unsure should I be about the answer I get out?
 
IMPACT OF DIAMETER VS. PITOT PRESSURE
In this equation, a percentage error in measurement of a diameter could have an outsized effect on the resulting flow since diameter is squared.
 
To run an error propagation on a formula involving variables which are multiplied together, we square the relative uncertainty (change in a measurement divided by the measurement), square them, add them together, and square out the result. 

​EXAMPLE: 60 PSI GAUGE
So, let’s say we ran a flow test where we were certain in the Coefficient of Discharge (0.90), we measured and were confident in the diameter of 2.5 inches (within a 1/16th of an inch), and took a pitot reading of two side outlets each at 8 psi using a 60 psi gauge with 1% accuracy.
​
Practically speaking, that’s a very reasonable amount of tolerance of a normal hydrant flow test or fire pump test.
​
With those results, we would calculate a total flow estimate of about 950 gpm. 

​How precise is that flow?

(Error in flow test reading measuring opening within 1/16” and pitot with 60 psi gauge)
​

So, with a variation of + 59 gpm, our resulting flow estimate would be 950 gpm + 59 gpm, or a resulting range of between 890 gpm and 1010 gpm.  
 
That’s a pretty wide variation – and it’s certainly a lot wider than I would have expected considering we’re using a 60 psi gauge with 1% accuracy.
 
EXAMPLE: 100 PSI GAUGE
What would happen if we used a 100 psi gauge with 1% accuracy?

(Error in flow test reading measuring opening within 1/16” and pitot with 100 psi gauge)
​

​EXAMPLE: 300 PSI GAUGE
Taken to an extreme – what if we used a 300 psi gauge to measure pitot? A bad idea for sure (it’s nearly impossible to read sensitive low amounts, and likely in the least-accurate portion of the gauge. But just for kicks:

​EXAMPLE: 60 PSI GAUGE WITH IMPRECISE DIAMETER
Now, what if we were less confident in the actual inside diameter of the hydrant side outlet? What if we thought it was 2.5”, but only within an 1/8th of an inch? With our 60 psi gauge:

(Error in flow test reading measuring opening within 1/8” and pitot with 60 psi gauge)
​

Yikes! Did you notice that?
 
Even with a 60 psi gauge, if we only know the inside diameter within an 1/8th of an inch, it’s worse than using a 100 psi gauge.
 
Knowing the precise inside diameter is important as it has a huge effect on the level of precision.
 
HOW DO WE IMPROVE PRECISION?
Based on the inputs – there are a few key ways to improve the precision of flow test readings when we use pitot gauges to estimate the amount of flow.

I’m interested in writing more on this in the coming weeks, but there are a number of ways in which we can improve the precision of our flow testing and have more confidence in our results.
 
#1 MEASURE THE OPENING SIZE
First – and probably the most important based on our calculation – is to know the exact diameter of the orifice opening.
If we are flowing out the side of an outlet, we actually need to measure, with precision, the inside diameter of that opening. As I’ve been told, not all inside diameters are equal. They depend on the exact make and model of a hydrant.

I’ve made this mistake before and assumed all 2.5” side outlets are the same inside diameter.

To improve precision, take a careful measurement of the exact inside diameter of the opening down to the 1/16th of an inch.

Alternatively, using a factory-created attachment with a factory-milled opening will help define and make that variation go away.

A known diameter with a very tight factory tolerance helps us reduce or eliminate this concern altogether.

#2 USE SMALLER RANGE GAUGES
In general, we want to use the smallest range for the gauge possible.

Using a 300 psi gauge to measure anything within 0-30 psi is problematic. Not only is that a less-accurate range for a gauge (near the ends), it’s extremely difficult to read. The tickmarks just become too small to read well.

Instead, we want to use the lowest gauge range that’s possible for the test.

If we’re expecting results below 100 psi, can we use a 100 psi gauge instead of 200 or 300?

If we’re measuring pitot and expecting values under 60, can we use a 60 psi gauge?

Even a 30 psi gauge?
​
The bigger the tickmarks and the smaller the range, the better we’re going to be able to see and read the results.

#3 LARGER-DIAMETER GAUGES
This goes against my “travel with small things” concept, but larger-diameter gauge faces are so much easier to read in the field.

They cost more. They’re bigger. But man are they easier to pull values from.

Again – on an important fire pump closeout with many people all watching – having nice clear results to prove the system works as it should helps.
 
#4 USE CALIBRATED GAUGES
For fire pump testing, NFPA 20 requires that all gauges undergo annual calibration testing and be accurate within 1 percent. (NFPA 20-2022 Section 14.2.6.1.2)

For fire hydrant flow tests, that same mandate doesn’t necessarily apply. NFPA 291 is a recommended practice, and requires calibration within 12 months, but is not necessarily enforceable in the same way that NFPA 20 is.

Now, if you’re on a federal project and NFPA 291’s “shoulds” become “shalls”, then there are enforceable teeth.

But for private practice work, many flow tests are simply run with whatever gauge is on the truck that day.

Using a calibrated gauge will obviously hone in for more precise measurement.
 
#5 USE STREAM-STRAIGHTENERS
NFPA 291 now specifically states a preference for playpipes or stream straighteners to improve the accuracy of readings.

Not only do these address the precise opening sizes we talked about earlier, but they hold the pitot measurements in a fixed-in-place mounting position.

This also means we should be measuring at exactly the right center-of-stream location.

This is explicitly listed now in NFPA 291 (2022) Section 4.6.2.
 
SUMMARY
Doing a little error propagation highlights a few things about the measurement process in a calculated way.

We can look at the accuracy of our input measurements an in turn, get a level of confidence about the resulting range of flow from those measurements.

The more precise we are able to measure, the more confidence we have in the result – which is both an obvious ‘gut-feeling’ but can also be mathematically proven.
 
YOUR TAKE
I’m interested in your take.

What are your tips for more accurate readings?

What stories do you have about fire pump acceptance testing or hydrant flow tests in this regard?
 
NEXT STEPS
I’d like to venture down this rabbit hole just a little further.

My next thought is to apply the error propagation concept into a quick calculator tool where you could see your error range yourself – and experiment with different situations.

You might just find an error range based on your normal test equipment that could present your test results in a more appropriate and transparent way.

That's TBD (to be developed).
 
Thanks for reading – and, as always, for fighting the good fight. Have a great rest of your week.
​
- Joe

 
#1 SHOW THE MEANS OF FORWARD FLOW (ADDED IN 2019)
A means of conducting a forward-flow test has long been required, but historically overlooked or was possibly achievable by flowing out of a fire department connection or main drain (for very low hazards).
 
We talked about the big change for a fixed means of forward flow that was introduced in 2019 and clarified in 2022.
 
How does this affect shop drawings?
 
Well, we now need to locate and identify the means of forward flow on the plans [NFPA 13-2019 Section 27.1.3(25) and 2022 Section 28.1.3(18)].

Last week we updated the NFPA 13 shop drawing checklist with references to NFPA 13 2019 and 2022 Editions.
 
While code updates like this are traditionally modest, the NFPA 13 Committee revamped the entire list of requirements for “working drawings” in the 2022 Edition. It was gutted.
 
We’ll expand on that more next week.
 
This week I’d like to key in on one very impactful change that I think will affect many of us in how we design systems going forward.
 
FORWARD-FLOW REQUIREMENT HISTORY 
A forward-flow test has long been required in NFPA 25 (dating back to at least 2002).
 
The purpose of the test is to verify that a backflow preventer is capable of fully-opening in a fire – or at least to the extent that it allows enough water to flow to satisfy the sprinkler system’s demand.
 
A means of conducting a forward-flow test has long been required, but not necessarily readily implemented. For many lower-hazard systems, it was a test that was possible by flowing out of a fire department connection or main drain.
 
WHY NOT FLOW OUT THE FDC?
White it was possible to do a forward flow through an FDC, this approach was never practical. I can’t stand on a high horse here – it was the approach I long used from a design perspective.
 
It’s not practical because conducting a forward-flow test out of an FDC would typically require a system to be shut off, drained, check valve reversed, put back into service, tested, shut off, drained, check valve put back into place, and put back into service. And that was if the clappers on the FDC were removed or restrained in a way to allow enough water to pass through. It’s a tall ask.
 
USE THE MAIN DRAIN?
Flowing out the main drain could be a solution for forward flow, but practically speaking how much water can flow through a 2-inch main drain, especially if there’s an OH1 or OH2 demand? Do we have a way to verify how much water we’re flowing, so that we know the test passed?
 
Some have used our own calculator to estimate the amount of water flowing through a main drain by using this orifice flow calculator - https://www.meyerfire.com/blog/a-new-fire-sprinkler-test-drain-flow-calculator
 
That calculation is based on pressure flowing through an opening – either an orifice or pipe diameter – and doesn’t incorporate the losses that occur through the length of a main drain or the fittings along the way. It’s going to be too generous on the amount of flow coming through a main drain – which is good if we’re wanting to know how much water a plumbing drain needs to accept – but bad if we’re trying to prove forward flow based on it.
 
I would suspect that a supply-side calculation (where the available pressure dictates the flow) through a fully-open main drain would be the best way to predict hydraulically how much flow a main drain could flow. If that’s well above the system demand (including hose allowance), then a main drain could be the means to flow.
 
But a 2-inch main drain is very likely not an answer for forward flow for most systems.
 
I’ll leave that discussion open – perhaps there’s a tool we could construct to account for main drain losses and perform that supply-side calculation.
 
PERMANENT MEANS FOR FORWARD-FLOW
Somewhat fortunately for those of us who like black and white guidance (myself included) –the NFPA 13 committee closed up the gray area in the 2019 Edition by requiring that an arrangement for conducting the forward flow test, at the minimum flow rate of the system demand (including hose allowance), would be provided “without requiring the owner to modify the system to perform the test.”
 
This comes from NFPA 13-2019 Section 16.14.5.1.1.
 
In the 2022 Edition, the committee went further.

A 2-1/2” HOSE CONNECTION FOR EVERY 250 GPM 
A test connection is now required for forward flow tests, where now a 2-1/2” hose valve is required for every 250 gpm (950 L/min) of system demand. This total flow must include the hose allowance where applicable. Generally, if there are interior hose valves, then this would need to get added in.
 
So - an Ordinary Hazard Group I system that may have a demand of 270 gpm (with 250 gpm outside hose allowance), would still need two 2-1/2” hose valves for the forward flow test fixed in place downstream of the backflow preventer.

For larger systems, or those with interior hose connections? We could be looking at three or more hose connections just for forward flow. This comes from NFPA 13-2022 Section 16.14.5.1.1. That’s a noteworthy change.
 
For a code-minimum, sprinkler-system-only type of project, that’s a tangibly different cost and look to a part of the system.
 
Does this have to be a test header on the outside of the building? Not necessarily, though that would be nice for future testing.
 
Could the hose valves be on a riser in a room that has exterior access? Depending on the room and goals for the building – that could be reasonable.
 
There are two provisional sections that allow existing hose connections to be used for the test (16.14.5.1.2), and other means to test are allowed “as long as the system doesn’t require modification to perform the test and is sized to meet the system demand.” The later comes from NFPA 13-2022 16.14.5.1.3.
 

HAVING TEETH 
But in general – we don’t have a “use the FDC” workaround any longer.
 
For those in IT&M, we finally have a sticking point to give an ability to do this test without tinkering with the system.
 
For those in design, we finally have a magic section of code that we can show to justify providing a means of the forward flow test.
 
For those in review and inspection, we have the teeth to enforce it.
 
Hopefully, in the long-run, having systems tested for forward flow will identify backflow preventers aren’t functioning and we no longer have them in buildings ready to fail when a fire happens.
 
Hopefully, this pushes buildings to a bit safer and helps us a be a little more confident in the system’s ability to fight a fire.
 
SHOW ON WORKING DRAWINGS
While the means is an installation question – NFPA 13-2022 Section 28.1.3(18) requires that working drawings locate and identify the means of forward flow.
 
It’s no longer a “how do you plan to do this test?” type of comment and will soon be “show the location and label the means of forward flow, per 28.1.3(18).”
 
MY FORWARD-FLOW STORY
Are we really just testing the backflow preventer here?
 
Well, yes. In part.
 
But actually flowing an entire system demand tells us quite a bit. It means that our water supply is capable of flowing the full system demand, and all the pipe in-between the water supply and the backflow is also open-enough to flow the full system demand.
 
I once had a project where a tap was made to the city supply main. It was a live tap or “hot tap,” where a drill punctured the side of the city main and a new 6” street valve was installed and our 6” underground came in and fed the building.
 
It was a brand-new 3-story building that was going to have overnight guests.
 
The tap wasn’t fully-made. In fact, as we found out later through a lot of cost and trouble, only a ¾” pilot drill bit made it through the city main. It wasn’t all the way drilled-in.
 
Instead of a 6” tap, we had a ¾” tap.
 
Static pressure to the building was fine.
 
We could run a main drain test just fine (the residual dropped, but the main drain isn’t flowing all that much). Remember – the initial main drain test sets the threshold to check against in the future.
 
We could flow the inspector’s test just fine.
 
When we conducted the forward flow test and opened a couple 2-1/2” hoses – we had no water. No pressure at all.
 
It wasn’t until we conducted the Forward Flow test that we knew there was a problem.
 
Where it not for the Forward Flow test, we would have had a brand-new building, which, by all other measures we would have thought was designed and installed properly – all protected by a system with water that was squeezed through a ¾” hole.
 
While the backstory of testing the Forward Flow may be more about the backflow preventer, the test does give us confidence in the supply up through the backflow preventer being able to handle the system demand.
 
If we measure the flow coming from the forward flow, and also stick calibrated gauges on the upstream cock and downstream cock of the backflow – we can know a whole lot about the health of our system that day.
 
What’s the static pressure? What’s the loss through the backflow? What’s the base of riser pressure at the system demand? How does that compare to our design?
 
We can get a lot of information just from this one test.
 
END SOAPBOX
That’s my soapbox rant for today. As with all we write and do on this site, I hope you’ve found it helpful.
 
Keep fighting the good fight, and have a great rest of your week.
 
- Joe ​

Have you had a project with an overhang that needed sprinkler protection and extended just beyond the throw of a dry sidewall sprinkler?
 
It’s a smooth, flat or nearly-flat overhang that’s, say, 21’-6” wide, and in an environment that will dip below 40 degrees F at some point.
 
What are your options then?
 
OPTIONS
All of the extended coverage dry sprinklers we know on the market cap out at 20’-0” horizontal throw. That would have been our best option.
 
We could look at using a dry system. There’s the additional cost of the valve, slope requirements, a hit on the remote area size, more corrosion potential – and on and on. It’s costly.
 
We could look at an anti-freeze system. Those come with more restrictions than they used to, but at a minimum would involve an RPZ and now pre-mixed antifreeze solution. Additional cost.
 
Heat trace the pipe? That’s problematic, at best. It needs to function 100% of the time that it’s needed, or pipe will freeze. It needs to be supervised. It needs to be maintained. And when in conjunction with pipe insulation it looks terrible.
 
In short, an overhang that’s just beyond the reach of a dry sidewall sprinkler can take us to a whole new cost tier in the design of a sprinkler system.
 
CODE-COMPLIANT CREATIVITY
We had just this situation on a project a few weeks ago, and tried to think creatively to get a code-compliant solution that’s best for the owner, yet doesn’t spike the cost for a dry sprinkler system that only serves four sprinklers.
 
Now normally, sprinkler design tends to be a one way street. An architect designs a building. It gets bid and handed down to the sprinkler contractor. The sprinkler contractor “makes it work” with what they’ve been given.
 
If a consultant is on-board, this would be a great opportunity to pick off challenges like this and advice the architect and owner on ways to mitigate this cost spike for a small project. Perhaps the overhang is designed at 19’-6” instead of 21’-6”. Perhaps they build it with all non-combustible materials if it otherwise didn’t have storage below.
 
Those could be helpful changes that reduce the overall cost in a major way, but may not be a major detriment to the owner’s goals for the building.
 
#1 SHORTEN THE OVERHANG
Regardless, we suggested that the width of the overhang be actually shortened to allow a sidewall’s throw to cover the distance and prevent the need for a whole dry system.
 
That didn’t go anywhere.
 
#2 EXTEND THE REACH OF A DRY SIDEWALL
We then asked if a soffit could be built to allow a sidewall it’s spacing of no more than 20’-0”.
 
The soffit wouldn’t have to be heated. It could simply be framed (hopefully of non-combustible studs) with sheetrock or a “Hardie Board” or some other skin. It could be almost completely empty on the inside.
 
The goal would be to give a dry sidewall sprinkler a back to collect heat and be installed properly.
 
KEY RULES
There’s a few notable rules that come into play here, though.

1. Extended coverage sidewalls need to be within 6” (150 mm) of the wall which they are mounted (Section 11.3.5.1.2.1, NFPA 13 2022 Edition).
2. If the soffit is more than 8-inches (200 mm) in width, then a sprinkler is required below the soffit (also Section 11.3.5.1.3.1, NFPA 13 2022 Edition).

 
So working backwards, a soffit that is say, 2’-0” wide and 2’-0” tall would allow a dry sidewall sprinkler to:

1. be mounted to the side of the soffit within the 6” of the ‘wall’ which it is mounted,
2. allow the height of the sidewall to be 6” from the deck above,
3. allow the dry sidewall length to be long-enough to have the dry barrel run all the way through the width of the soffit and extend into the warm heated interior space, and
4. limit the throw distance of the dry sidewall to less than it’s maximum of 20’-0”.

 
But then, we need coverage below the soffit too, right?
 
This could be accomplished with a flexible dry pendent, such as the V3517 dry flexible pendent sprinkler. Just like the dry sidewall, the flexible dry pendent could contain water back on the warm interior space.

DIGGING DEEPER
We also would want to offset these locations on plan, so a pendent isn’t immediately under a dry sidewall. Offsetting the locations in plan could help potential cold-soldering concerns.
 
We’d also want to be sure that both the dry sidewall and the dry flex pendent would be able to be replaced at some point in the near future. NFPA 25 used to require sample testing or replacement every 10 years starting at 10 years after installation, but the 2020 edition bumped that starting point up to 15 years and the 2023 Edition bumped it again to 20 years after installation (NFPA 25 2017-20 Section 5.3.1.1.1.6, 2023 Section 5.3.1.1.1.5).
 
To accommodate replacement and testing, we might need a way to get access to the inside and the soffit in the future (access panels or future cutout).
 
COST & CONSEQUENCE
After all this effort – will the soffit cost more? Sure.
 
Would it cost as much as a dry or anti-freeze system? No, it shouldn’t.
 
Does it help with corrosion and IT&M in the future, considering we wouldn’t have a dry valve and an additional nitrogen system or air compressor? Yes, that’d help too.
 
Just an idea that might help address those “in-between” situations that could spike cost for a smaller-sized project that otherwise wouldn’t need it.

What are your thoughts? Have you tried this before? What tips would you suggest?
 
Hope you’ve found this interesting and perhaps moderately helpful, and I hope you have a great rest of your week!

How do we solve the systematic problem we have with fire protection bid documents?

Some, if not much of the plans and specifications that go out for bid are generally helpful.

A quality set of fire protection bid documents:

• Attempt to clearly define the fire protection scope (highlight what is included, but also identify what is not)
• Communicate clearly, and unambiguously
• Aid the project by answering major questions
• Aid the project by identifying and addressing big challenges early-on
• Provide a biddable scope where contractors can bid “apples-to-apples”

These types of bid sets do happen.

But far, far too often, they don’t.

It’s systematic, and makes every step of the design and installation process far more difficult and far more costly than it could be.

NOT FAULTLESS
I don’t even want to pretend I’m not at fault here.

I’ve designed poor projects. I’ve slacked on coordination, and detailing.

I’ve glossed over parts of a project that I shouldn’t have glossed over. It’s been painful.

But this is something that we can change.

WHAT CONTRACTORS SAY
For some years now I’ve spoken with sprinkler contractors, architects, and consultants about this.

If you’re a contractor, especially if you work in estimating - you could provide countless examples of terrible bid documents. Bid documents that actually get in the way of you doing code-compliant, efficient work.

You could speak to this far better than I can.

In these conversations, over and over, I’ve heard one key feature that I think many consultants in the MEP space miss.

It is far better to have no fire protection bid documents, than to have bad fire protection bid documents.

NO FIRE PROTECTION BID DOCUMENTS?
That’s important, and counterintuitive.

It is far easier for a sprinkler contractor to look at a project and define their own scope, and put a price to it, than it is to try and bid a set of documents that:

• Are inconsistent
• Mandates something that’s not actually code compliant
• Mandates something that’s not actually possible to construct, or procure
• Describes industry methods or materials that are not actually available today

If that sounds too far, ask your closest estimator friend. They see this all the time.

How many projects do we see underground feeds piped 20-ft before rising up? How many times do we see Star, Central, or Gem still specified today, in 2024? How many times do we see projects wanting a fixed-price bid yet have zero information about the water supply?

How are those documents helpful to a bidder?

They’re not.

MY ANALOGY
The analogy that I’ve had in my head and finally am able to bring to life a little is the road, showing the different tiers of fire protection bid documents:

1 - NO FIRE PROTECTION BID DOCUMENTS
There’s the sidewalk on the left, where we have no fire protection bid documents.

Let’s say we have a single-family home with an NFPA 13D system. Scope is simple, perhaps we have no specific owner needs, and it’s unambiguous.

That type of project probably warrants no upfront, pre-bid fire protection involvement.

It wouldn’t have to just be a single-family home though.

What about an add & relocate job for a small retail space. Or a small office building.

Those can, and often do, work just fine without any upfront fire protection bid documentation.

Design-build all the way.

2 - QUALITY "PERFORMANCE SPECIFICATIONS"
Then we skip ahead to quality “performance specification” documents.

These do all the things we’ve talked about. They don’t necessarily show pipe or sprinklers, but they clearly define the scope, they communicate clearly, they answer major scope questions, they address and alleviate major issues or coordination challenges upfront, and they make it easy to put a price to the job.

That’s a quality set of “performance specifications”.

3 - QUALITY "FULL-DESIGN"
For high-end jobs, or high-hazard jobs, or critical function or high-visibility or unique jobs – perhaps we’re looking at a full-upfront design prior to bid.

Full-design isn’t free, nor quick, and isn’t necessarily the answer for every job.

But, as we’ve talked on this topic before; if it’s done well, and thoroughly, then fully-detailed plans can be a tremendous asset to a project. They can eliminate ambiguity and really dial-in exactly what work needs to be done.
 
AND... THE DANGER ZONE
What about the DANGER ZONE?

There’s a gap, and it’s in-between no bid documents and quality “performance specifications”. And that is the Danger Zone.

This is the lane of bad bid documents.

These are all the bad things. Inconsistent, boilerplate, confusing, inaccurate, unachievable, irrelevant, or not actually code-compliant.

What happens when we live in that lane?

We get hit by the proverbial bus.

Change orders. Litigation. Or much worse – a fire happens with major loss.

This is not the spot to be.

WHY DO WE STAY IN THE DANGER ZONE?
I’m fairly confident that those who live in that space don’t want to be there either.

They feel compelled because the client asks for fire to be included. They feel pressure because competitors are offering to do fire protection. They feel they can’t spend enough time on fire because there is hardly any fee there.

Honestly – these are all poor excuses.

If there isn’t enough money in the job to put together a quality set of fire protection bid documents – then don’t do them at all.

It is far better to have no fire protection bid documents, than to have bad fire protection bid documents.

HALF-BAKED DOESN'T HELP
Bad, sloppy, half-baked documents don’t help. They don’t solve anything. They get in the way.

If you’re the MEP who finds yourself in this area, having that conversation with an owner or architect and there’s just not enough fee to do quality work – then just exclude it entirely. If an architect insists that it get thrown in or done on a microscopic budget, then just ask them to hire a fire protection consultant separately.

Half-baking a set of documents is not worth the hassle or the liability. It also doesn’t actually help.

​When you do take it on, do it well. We all benefit from that.
 
YOUR TAKE
If you’re a sprinkler contractor or architect – I really want to hear from you.

Where do you land on this?

When projects have gone south or had major change orders – what happened?

Would being in a different tier have changed the result?

Comment below, would love to hear your take.
 
And, thanks, as always, for reading and being a part of the community here. We will get this right.

USE GOOGLE FOR FLOW TESTS & SITE PLANS
I sometimes (maybe often) have to learn things the hard way.

This tip today comes from the “Lessons Learned” file, where it took me two bashings over the head before I had my ‘aha’ moment. Forgive me if this is obvious and you've been doing this for years. Again, I have to learn things the hard way sometimes.

So what is it? What are we talking about? Clearly identifying the location of the water supply.

And the ‘aha’ answer – well it’s really simple and can be really helpful.

On many projects we use a flow test to get an idea of the available water supply. We use the available water supply curve to calculate how much pressure and how much flow we have available that can serve our suppression system (sprinkler, standpipe, etc).

Flow tests carry a whole lot of engineering nuance. A flow test is simply an instantaneous “point in time”. It doesn’t account for demand variations like the time of day, day of the week, or seasonal demand like the lawn irrigation system next door. We’ll save that conversation for another day.

One other key factor that a flow test carries is that it is highly dependent on the location from where the test was run.

DOES THE LOCATION OF A FLOW TEST MATTER?
If we have a large, looped supply, then the location horizontally may not play much of a difference. Say we have an Ordinary Hazard Group 2 sprinkler system and our main outside is a 12-inch looped main. The exact point which we tested isn’t going to affect our system all that much, because we wouldn’t get a lot of pressure loss in a 12-inch looped main when we’re only flowing 550 – 750 gpm.

What if we’re not looped? What if it’s a dead-end 6-inch main instead of a looped 12-inch?

Well, now our horizontal location could be critical. If our flow test is taken immediately adjacent to our building, then we have a high degree of confidence of what the water supply is doing right where we’re going to tap it.

But, if our flow test was actually taken 1,500 ft upstream and we have a dead-end 6-inch supply, then we need to calculate the loss through that entire dead-end supply. That could be a lot of pressure loss!

For example, for a 750 gpm sprinkler system, running friction loss for 1,500 ft of 6-inch pipe would lose 16.3 psi. That would have a major impact on most system designs.

So, suffice to say, it can be important to document exactly where a flow test was taken horizontally.

It also matters, however, in the other plane.
​
DOES THE ELEVATION OF A FLOW TEST MATTER?
There’s a chance, depending upon the project, that the horizontal location of a flow test may not play much of a factor in the system design.

But the elevation of a flow test?

That will always play a factor.

If our static/residual hydrant (gauge hydrant in the diagram) is actually 30-ft lower in elevation than our project site, that has major implications.

Let’s take a quick example.

We look at results from a flow test showing a static pressure of 60 psi with a residual pressure of 50 psi at 1,200 gpm. If that test was taken at the same elevation as our project (a big large flat open field, for example), then we would expect a pressure gauge at the riser to be somewhere around 58-60 psi when nothing is flowing. The pressure gauge and the original gauge hydrant are very close in elevation.

However, what if that test (those readings) was actually taken down the hill, at an elevation that was actually 30-ft lower than our project site?

We would have a lot less available pressure.

As we go deeper in a system, pressure increases. As we rise up within a system, pressure decreases.

So a riser that is approximately 30-ft above the gauge hydrant would have an expected pressure of around 47 psi (60 psi – 30-ft x 0.433 psi/ft).

That might not sound like much, but in some projects without a fire pump where we are already tight on the hydraulic calculations, this can be a major issue.
 
AN EASY SOLUTION FOR THIS
I’ve had two major project issues related to bad documentation of exactly where the flow test was taken. Most projects I see have a simple description for where a test was taken. It’s something like “at the corner of McKinley & Brower Streets” or “1000-ft east on Highway D from the flow hydrant”. Sometimes it’s a description like “on Highway T”.

Having an intersection will generally help us narrow down which hydrant was actually used in the test. Usually.

Having a description on the road doesn’t help us narrow down much, unless there’s only one hydrant within a half mile radius.

What is very, very helpful for narrowing down which hydrant was used? GPS coordinates.
 
USING GOOGLE MAPS
Within google maps, it’s extremely easy to precisely locate any point on earth. You don’t even have to go into Google Earth, like we did in an article to grab elevation here.
​
To grab any GPS coordinate on Google Maps, just right click and you’re presented at the top with the coordinates. Click on those coordinates to “copy” the coordinates where you can then paste them, as text, anywhere else.

​
​Now, you can paste them into your flow test report, paste them onto your site plan, your hydraulic calculation report, or anywhere else. You only really need to go four decimal places for the coordinates – anything more and you’re talking about less than an inch – which of course is far too precise for what we need here. 

​
​If later on, someone needs to verify a hydrant elevation, they can just copy and paste these same coordinates back into Google Earth (to get an elevation), or paste these right back into Google to get the location in Google Maps.

​
Using GPS coordinates for flow tests is extremely easy to do. What’s most important, though, is that by providing the coordinates for where the test was taken, you’re taking out so much ambiguity.

Construction documents are only created for communication. If they don’t clearly communicate, then they’re not serving their purpose.

I’ve only recently reached this ‘aha’ moment, but using the coordinates has already helped on recent projects.

What about those two major project issues? What was up with those?

One was related to a very poor description for where a flow test was taken (a flow test that I received from the city and failed to document well).

The other was a flow test that had been taken a good 1,000 ft upstream on a 6-inch dead-end main.

In either of these cases, had I correctly documented the exact location of the test, or had I received the exact location of the second test – we would have had no issues at all, because we could have accounted for these differences during the design of the project.

Hope this tip helps you avoid some headaches in the future, and that you have a great rest of your week!

​- Joe

Awhile back I wrote a piece on sprinklers in electrical rooms. At the time I was asked relatively frequently about when sprinklers are required or allowed to be omitted in electrical rooms.
 
I guess intuitively, we recognize that electricity and water don’t mix well. We don’t want to address one problem (fire) by creating a new hazard (electrocution) with water in areas that it doesn’t have to be.
 
In principle, I personally have just about always provided sprinklers in electrical rooms unless they were specifically requested not to be provided by the owner or AHJ; and in those cases, I followed the code path in the IBC or NFPA 13 accordingly.
 
It seems as though the premise behind not including sprinklers is when the type of electrical equipment present a relatively low hazard or fuel source, and there is no storage. In that situation, a combination of 2-hour fire-resistance-rated enclosure with approved fire detection (assuming a smoke and/or heat detector here) will mean that a fire within the room will be recognized, and the rest of the building will not be compromised as a result.
 
Providing pipe within an electrical room isn’t always an easy feat. NFPA 70 tells us that electrical equipment requires dedicated zones, and pipe shouldn’t be run above panels without drip pans or other methods of avoiding drip hazards above electrical equipment.

Now are sprinklers in electrical rooms problematic? Generally not (in my experience).
 
Can pipe routing be made to avoid electrical equipment? Usually yes. I try to only run one branch line into the room, most often above the door (since no electrical equipment is on the door), and stick pipe only above walking pathways within the room.

Does the code or standards express any concern or guidance on this? Yes, both the IBC and NFPA 13 address the situation.
​
One line that is included in the IBC specifically says that sprinklers “shall not be omitted from any room merely because it...contains electrical equipment”. To me, that’s a fairly explicit way of suggesting that the presence of electrical equipment alone isn’t a justification for omitting sprinklers. Now there are code allowances and necessary provisions to do so, but the suggestion is not to simply avoid sprinklers just because there is electrical gear.
 
Despite it being awhile since that article, I have had a few requests to make this one into a flowchart, which I’m happy to present today. A special thank you to Alex Riley, PE, who contributed to the code research for this flowchart.