How Many Dry System Inspector’s Test Valves?

3/13/2026

We have an EH1 dry system, and will be installing the inspector's test manifold with 4 outlets.

We know that it's 2 outlets from the two remote branch lines, but I do not see in NFPA 13 if we should tie the line together so only 1 Inspector's Test Valve (ITV) would need to be operated to flow all 4 outlets, or if we'd install 2 ITV's valves next to each other, 1 valve for each remote line so the air is exhausting through each line independently.

Any input would be appreciated!

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

9 Comments

Glenn Berger

3/13/2026 08:15:19 am

Someone will need to correct me if I am totally off-base here!

NFPA 13 (2025) Section 29.2.3.2 will be applicable.

Me thinks that you are confusing the Backflow Prevention Assembly testing requirements with the Inspector's Testing Requirements.

Glenn

3/13/2026 08:47:36 am

I got this one incorrect. Water Delivery Calculations Section 8.2.4.3.

Dan Wilder link

3/13/2026 08:23:41 am

My approach has been the lower picture and, in my mind, follows the wording from the standard:

Simulate two sprinklers from the remote branch line and two sprinklers from the next adjacent branch line.

I have tied these together into a single drain line, mostly because of all the data centers wanted hard piped drains to the exterior. The use of the drain line is to exhaust air so that the sight glasses show the water delivery so there has been no issues with sizing the drain.

I will state that because these are not typically in areas subject to freezing, I use the test connection setup with an additional globe valve at the bottom and the AGF 3011 to create the drum drip section valving in lieu of a separate drum drip as shown. If I can discharge outside, the setup shown works well.

M. Newell

3/13/2026 08:26:02 am

You would likely have 2 ITV. See Figure A.‍8.2.4.4. My thought is if you combined them together with a single valve you are limiting the flow to that single pipe vs taking the dual flow paths.

Donnie Brewer

3/13/2026 08:27:41 am

I think you are fine with option 1 by interconnecting the two providing you meet the time requirements for activation of the dry system. You only need water flow from a single sprinkler of the most demanding type head for the remote inspector test vale.

David Kendrick

3/13/2026 08:28:10 am

Likely to have better performance exhausting air/nitrogen from a single point.

Harkens to the past when gridded dry systems were accepted. They are not currently. The gridded dry system tended towards exhausting all the air and delayed the flow of water to the test outlet.

The goal is to verify the water to the most remote outlet. Banking against the system air.

Matt Hamilton

3/13/2026 08:30:03 am

Your second option is the correct way. You would have two ITV's installed, one for each two outlet manifold. 2022 NFPA 13 Figure A8.2.3.7 in the appendix shows it fairly well.

Jack G

3/13/2026 03:48:48 pm

2 nd way is how I d do it.
If the branches were sloping towards the system riser I would goose neck to the inspectors test.

Dave S

3/16/2026 10:58:04 am

I agree with the others choosing option 2 as it will give the best chance of meeting delivery times by exhausting air the fastest. But it does bring up some questions that I've always wondered but haven't had a chance to test in the field or via one of the water delivery programs:
1. Assuming the branch line is larger than 1" does it make a noticeable difference in delivery time keeping the IT pipe and valve the same size as the branch line versus reducing to 1"?
2. Does adding a couple of elbows as Jack suggests (and I agree) affect the delivery time?

Leave a Reply.

Home
Our Cause

The Blog
The Forum

PE Exam Prep
The Toolkit
MeyerFire University

Pricing
Login
Support
Contact Us

MeyerFire.com is a startup community built to help fire protection professionals shine.
Our goal is to improve fire protection practices worldwide. We promote the industry by creating helpful tools and resources, and by bringing together industry professionals to share their expertise.

MeyerFire, LLC is a NICET Recognized Training Provider and International Code Council Preferred Education Provider.
All text, images, and media Copyright © 2016-2025 MeyerFire, LLC

We respect your privacy and personal data. See our Privacy Policy and Terms of Service. The views, opinions, and information found on this site represent solely the author and do not represent the opinions of any other party, nor does the presented material assume responsibility for its use. Fire protection and life safety systems constitute a critical component for public health and safety and you should consult with a licensed professional for proper design and code adherence.

Discussions are solely for the purpose of peer review and the exchange of ideas. All comments are reviewed. Comments which do not contribute, are not relevant, are spam, or are disrespectful in nature may be removed. Information presented and opinions expressed should not be relied upon as a replacement for consulting services. Some (not all) outbound links on this website, such as Amazon links, are affiliate-based where we receive a small commission for orders placed elsewhere.

How Many Dry System Inspector’s Test Valves?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES