Contact US

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.

Students Click Here

Ammonia Local Exhaust Design

Ammonia Local Exhaust Design

Ammonia Local Exhaust Design

Hello -

we use a distillation process to purify liquid ammonia before it's distributed as a gas.  I need to put a local exhaust system over the whole process.  

I know all the dimensions, but I need to determine fan size.  OSHA standards state that you should stay under the TLV number & size your ventilation to meet that requirement.

How do I determine the ventilation flow rate required to maintain the ammonia concentration in my hood below the TLV standard?


RE: Ammonia Local Exhaust Design

The hood design determines the flow rate. This along with the rest of the duct system determines the fan size. The hood has to remove all of the contaminated air and an enclosed hood around the source does this the best. The flow rate has to be larger than the rate of fume generation and also to ensure the minimum control velocity at all hood openings. Hood design is situation specific and many examples with guidelines can be found in the Industrial Ventilation Manual issued by the ACGIH. The TLV value is a standard for the dilution ventilation of the room air (the air the worker breathes).


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! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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