System Valve Open or Closed During Churn Test?

5/9/2023

During fire pump testing, for the churn test, should the system valve (on discharge side of course) be open or closed?

I lean towards it being open, as I would rather know the weak point during a test than during an actual fire event.

Here's my pro/con list to keeping the valve open:

Pros (keeping valve open)

Could be required by Insurance provider/AHJ
Discovery of weak points in system rather than a real event
Closed valve creates in impairment, self-performing facilities risk leaving the valve closed

Cons (keeping it open)

Possible over pressurization due to incorrect fire pump settings
Older systems with compromised underground systems could increase
If verification of fire pump is the purpose, why subject the rest of the system to churn pressure and possible water hammer if not required

Thanks in advance!

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15 Comments

Chris Logan link

5/9/2023 08:28:01 am

Isolating the fire pump discharge creates an impairment, which would require verification that the valve is open after testing.
I keep them open, if something is going to break, rather it happen when someone is on-site, then During a fire.

Glenn Berger

5/9/2023 08:31:33 am

I prefer to keep as many valves in the open position as possible.

Todd E Wyatt

5/9/2023 08:39:06 am

The scoping Code (e.g. 2021 IBC) determines if a building requires a Fire Pump and which referenced standards (e.g. 2019 NFPA 20) shall apply to the “design, installation and operation” of that “fire protection and life safety system.”

The “No Flow (Churn, Shutoff)” definition is as follows :

3.3.42* No Flow (CHURN, Shutoff).
The condition of zero flow when the fire pump is running but the only water passing through the pump is a small flow that is discharged through the pump circulation relief valve or supplies the cooling for a diesel engine driver.
A.‍3.3.42 No Flow (CHURN, Shutoff).
A small discharge of water is required to prevent the pump from overheating when operating under no flow (CHURN) conditions.

“Churn” is referenced (16) times in 2019 NFPA 20.
• (4) times in Chapter 2 Definitions
• (6) times in Chapter 4 General Requirements
• (1) time in Chapter 10 Electric-Drive Controllers and Accessories
• (1) time in Chapter 12 Engine Drive Controllers
• (2) times in Annex C - Fire Pump Room Connectivity

Of these references, Chapter 4 General Requirements seems to address the condition of your inquiry.

“OPEN POSITION” is referenced (4) times in Chapter 4 General Requirements ...

4.16 Suction Pipe and Fittings.
4.16.5* Valves.
4.16.5.2 Valve Closure Time.
4.16.5.2.1
Listed indicating valves shall not close in less than 5 seconds when operated at maximum possible speed from the fully OPEN POSITION.
4.16.5.2.2
Valves with an automatic means to operate the valve shall not close in less than 5 seconds when operated at maximum possible speed from the fully OPEN POSITION.

4.17.10 Low Suction Pressure Controls.
4.17.10.4
The friction loss through a suction pressure regulating valve in the fully OPEN POSITION shall be taken into account in the design of the fire protection system.
4.17.10.5
System design shall be such that the suction pressure regulating valve is in the fully OPEN POSITION at the system design point and at 100 percent of rated flow.

... but none directly referencing the “No Flow (CHURN, Shutoff).”

5/9/2023 08:39:43 am

REFERENCES

2021 IBC

Chapter 9 Fire Protection and Life Safety Systems
Section 901 General
901.1 Scope
The provisions of this chapter shall specify where fire protection and life safety systems are required and shall apply to the design, installation and operation of fire protection and life safety systems.
Section 902 Fire Pump and Riser Room Size
Section 913 Fire Pumps
913.1 General
Where provided, fire pumps for fire protection systems shall be installed in accordance with this section and NFPA 20.
Exception: Pumps for automatic sprinkler systems installed in accordance with Section 903.3.1.3, or Section P2904 of the International Residential Code.
913.5 Acceptance Test
Acceptance testing shall be done in accordance with the requirements of NFPA 20.

2019 NFPA 20 Standard for the Installation of Stationary Pumps for Fire Protection

CHAPTER 4 General Requirements
4.1 Pumps.
This standard shall apply to centrifugal single-stage and multistage pumps of the horizontal or vertical shaft design and positive displacement pumps of the horizontal or vertical shaft design.

4.5 Certified Shop Test.
4.5.1.5*
For self-regulating variable speed fire pump units, two additional certified test curves showing the flow, net pressure, power, and speed shall be provided for each pump operating under the following conditions:
(1) In self-regulating variable speed mode with the pump unit operating at constant discharge pressure, as measured by the discharge pressure transducer, through the design duty, and all flow rates from CHURN beyond 150 percent of rated flow until the maximum power draw is reached
(2) In self-regulating variable speed mode with the pump unit operating at constant boost pressure through the design duty, and all flow rates from CHURN beyond 150 percent of rated flow until the maximum power draw is reached.

4.7 Pumps, Drivers, and Controllers.
4.7.7* Maximum Pressure for Centrifugal Pumps.
4.7.7.1
The net pump shutoff (CHURN) pressure plus the maximum static suction pressure, adjusted for elevation, shall not exceed the pressure for which the system components are rated.

4.13 Circulation Relief Valve.
4.13.1 General Requirements.
4.13.1.1*
Where an electric variable speed pump is installed, the automatic circulation relief valve shall open at the minimum speed.
4.13.1.2
Unless the requirements of 4.13.1.8 are met, each pump(s) shall have an automatic relief valve listed for the fire pump service installed and set below the shutoff pressure at minimum expected suction pressure.
4.13.1.3
The valve shall be installed on the discharge side of the pump before the discharge check valve.
4.13.1.3.1
For multistage multiport pumps, the automatic circulation relief valve shall be installed before the discharge check valve for the last port and set below the CHURN pressure of the first port.
4.13.1.4
The valve shall provide sufficient water flow to prevent the pump from overheating when operating with no discharge.
4.13.1.5
Provisions shall be made for discharge to a drain.
4.13.1.6
Circulation relief valves shall not be tied in with the packing box or drip rim drains.
4.13.1.7
The automatic relief valve shall have a nominal size of 0.75 in. (19 mm) for pumps with a rated capacity not exceeding 2500 gpm (9462 L/min) and have a nominal size of 1 in. (25 mm) for pumps with a rated capacity of 3000 gpm to 5000 gpm (11,355 L/min to 18,925 L/min).
4.13.1.8
The requirements of 4.13.1 shall not apply to engine-driven pumps for which engine cooling water is taken from the pump discharge.

4.20 Relief Valves for Centrifugal Pumps.
4.20.1* General.
4.20.1.1*
Pressure relief valves shall be used only where specifically permitted by this standard.
4.20.1.2
Where a diesel engine fire pump is installed and where a total of 121 percent of the net rated shutoff (CHURN) pressure plus the maximum static suction pressure, adjusted for elevation, exceeds the pressure for which the system components are rated, a pressure relief valve shall be installed.

Chapter 10 Electric-Drive Controllers and Accessories
10.5 Starting and Control.
10.5.4 Methods of Stopping.
10.5.4.2.1
Automatic shutdown shall be permitted only in the following circumstances:
(1)*During automatic testing in accordance with 10.5.2.7
(2) Where approved by the authority having jurisdiction
A.‍10.5.4.2.1(1)
Although the pump is allowed to start and stop automatically during CHURN testing, 4.3.1 requires qualified person(s) to be in the pump room to monitor conditions while the pump is running.

Chapter 12 Engine Drive Controllers
12.7* Starting and Control.
12.7.5 Methods of Stopping.
12.7.5.2* Automatic Shutdown After Automatic Start.
Automatic shutdown shall not be permitted if starting and running causes are present.
12.7.5.2.1
Automatic shutdown shall be permitted only in the following circumstances:
(1) During automatic testing in accordance with 12.7.2.7.
A.‍12.7.5.2.1(1)
Although the pump is allowed to start and stop automatically duri

Dan Wilder

5/9/2023 08:42:48 am

Jockey pump stop pressure should be Pump Churn + Static pressure.
Jockey pump start pressure should be 10PSI less than Jockey Pump stop pressure.

System components should be tested to 175PSI or 50PSI or static conditions. Anything downstream is already under those higher pressures and should have already been tested in excess of those same conditions.

I would argue that initial pump testing would be isolated to within the fire pump room to avoid any issues as you noted. Actual commissioning, it shouldn't matter. Anything after on the ITM side should not matter either but why allow so many unknowns if not required to (or there is strong protection language in your proposal)?

The question is very relevant as to the possibility of issues, but that is where the Owner responsibility for the ITM aspect is applicable. Companies will close valves to avoid the liability of discovering the "weak points" in areas that they are not responsible for, especially when they are not actively in the area.

A clear checklist for any testing activities (owner or ITM company) resolves much of this.

moises OLMEDA

5/9/2023 11:32:27 am

I agree with Dan

Adam Tuomala link

5/9/2023 10:48:10 am

Open... Plenty of references above.

Franck

5/9/2023 12:29:27 pm

Open.
When tests were performed with the valve closed, I always made a recommendation to keep it open.
Having it closed means you need to reopen it at the end of the test. And there are many possibilities to forget to reopen it (urgent call during the test. you stop the pump and forget to reopen the valve. Will be found in… one week (or longer) at the next test = unknown impairment for quite a long time).
In addition, if a fire unfortunately starts during the test, there will be no water delivered until the valve is reopened… resulting in more fire damages and more water damages with more sprinklers open…
Probability ? Not so low if you consider testing the pump 30 min every week (= 0.15%, which is much more than winning the lottery).

For all the cons, as indicated above, it is better to found it during a test than during a fire. With the pump starting with only one or 2 sprinklers operating, the delivered pressure will be very close to the pressure at churn !
So if you don’t want to burst your system by testing the pump a5 churn, you may burst it when 2 sprinklers will be in operation…

Pete H

5/9/2023 02:50:10 pm

Just adding another vote for "open".

Matthew Bass

5/10/2023 07:32:54 am

in my opinion, those that say it should be closed haven't been in the field enough to know why it SHOULD be open and like many said, Open is right in NFPA 25 and only closed during testing if the PRV is dumping too much water to meet fire pump ratings. Then and only then should you close the discharge valve if closing the PRV down will increase pressures above 175PSI. I've always told customers and techs that leaving the valve open is as it should and show me references to back up your opinion of it being closed. If you can't back it up with standards and references, then you shouldn't be closing it or if you ever had to go to court and explain, that you just used your opinion and not facts. Valve open here all day. And like Chris said, I want things to fail while testing as that is showing issues that need to be fixed. Not during a real event.

James Art link

5/10/2023 10:36:27 am

Yes, leave it open.
I did have a rusted branch line fail at a chemical plant during a pump test, fortunately in an area where water damage was not an issue, but while the maintenance people were right there, not during a fire.

And I have seen many valves closed that should be open.
(One was a to the hydrant at a branch office of my company!)
Often the culprit was a plumber who only cracked open a valve, to let pressure build up slowly, but didn't come back to finish.
Q. Does that make sense?
Are some plumbing systems so weak they will fail during filling?
Many fire systems have an FDC

Bill Cary

5/10/2023 10:55:45 am

From a property insurance viewpoint, churn testing is an impairment of the water supply unless there is a 2nd fire pump on the system. The catastrophic 1985 Milliken Live Oak Fire in LaGrange GA occurred while fire pumps were impaired for testing.

The only time valve closure is needed is annual testing of variable speed fire pumps when the PLD is disabled for the NFPA-25 required 3-pt flow tests.

Anthony

5/11/2023 07:14:25 am

Great case study reference always good to have an opinion backed up by real world data!

Open as everyone else has said.

Jose Garcia

5/11/2023 10:44:00 am

I prefer to inform my client of the pros and cons and let them decide what to do in this case. If a pipe or fitting bursts during the test and I make the decision by myself, my client may hold me responsible for the damages

Phil Watkins

6/4/2023 03:48:11 pm

Open.

The system should be siting at closed valve pressure anyway (pump churn pressure plus static gain from fire water tank when full). If its not, then your jockey pump should be re-set accordingly (this is a clear NFPA and BS/EN requirement).

You shouldn't experience surge pressures (or not significant ones) assuming you are starting pumps either manually or by automatically by dropping mains pressure.

System Valve Open or Closed During Churn Test?

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