INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

(OP)
There is one major difference between deluge and closed head system when using foam. With Deluge system, when the system operates, all all head receive foam solution. Only those heads actuated will receive foam solution on a closed head system.

In closed head system, a 4" ratio controller can be used so there must be a minimum flow before foam is generated. With each sprinkler head discharging approximately 16 gpm, at least 25 heads must open to ensure correct operation of foam system. This is a major disadvantage when using bladder tank with closed head foam sprinkler system.

A solution to this issue is to use an Ultra-wide proportioner instead of a ration flow propertioner. The Untra-wide proportioner will proportion correctly at a minimal flow of 20 gpm which is typically one sprinkler head discharging.

Now my question is as follows

1. Is Ultra-wide proportioner is expensive than ratio proportioner

2. Is it easily available in the market

3. Are are any operational and maintenance issues with it.

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

Ultra-wide ratio controllers are very useful when you're trying to proportion AR-AFF from a bladder tank with a closed-head system. Stuff is like molasses. NFPA 16 requires, among other things, that the proportioning system operates correctly with only the most remote four sprinklers flowing for closed head systems.

To answer your questions:

1 - yes

2 - no more difficult to procure than any other foam system components

3 - Not that I've encountered

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

(OP)
Thanks skdesigner.

If we are using closed head sprinklers, AHJ will require an application area more than 0.16 gpm/sft. Therefore, I am planning to use foam density as 0.3 gpm/sft for foam calculations. Lower density with water will result in smaller pump and tank, can I use water density as 0.16 gpm/sft with this application.

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

What are you trying to protect? The protection is based on the occupancy not just some number you pick.

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

(OP)
You are quite right LCREP.

This is a chemical warehouse where hazardous and flammable chemicals will be stored in a racking system which is around 5 m and warehouse height is 6.5 m.

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

OK so what standard are you using and what is your design based on the standard. In the USA we would use NFPA 30 or FM Data Sheet 7-29.

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

(OP)
We also use NFPA 30 here for this application.

Since sprinkler system is also serving to the tire storage along with chemical warehouse, as per occupancy classification, it can be classified as an ordinary hazard, group-2 (Tire storage & Chemical plant-ordinary)(please verify).

Based on commodity classification, it can be classified as Group B commodity mainly due to the tire storage in an adjacent small storage room.

In rack sprinklers will not be provided as warehouse height is only 7.5 m.

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

Buildtech2

It appears we are in the same place as we were a few weeks ago...

http://www.eng-tips.com/viewthread.cfm?qid=420936

Have you reached out to a fire protection professional yet??

RE: Closed Heads (Wet Type) Water Foam Sprinkler System with Ultra-wide proportioner

(OP)
You are quite right LCREP. Now our client is directly dealing with the firefighting specialist for designing as water foam sprinkler system is a pre-engineered system to be designed and installed by the specialsit but I am doing some background study as final design package will come back to me for the final review.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close