×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Toxic Gas Detector Time Delay

Toxic Gas Detector Time Delay

Toxic Gas Detector Time Delay

(OP)
Hello Friends,

We have Ethylene Oxide EO toxic gas detectors (GDT)in side plant. These is deluge activation linked to these EO Toxic gas detectors. Once these gas detectors 10 ppm (2 time of STEL) value it will activate Deluge system.

EO detectors have inherent cross sensitivity issue and we are facing false activation of deluge.

Is there any possible solution to avoid this?

We are intended to put time delay for 1 min or 2 min, if 10 PPM Value stay for more than 1 or 2 min then deluge to activate.

or is it safe to raise the GDT Deluge activate value to 50 ppm?

Please share your experience.

RE: Toxic Gas Detector Time Delay

STEL refers to average concentration of 5ppm over time period of 15 minutes, hence you should not have a single detector triggering deluge at any instantaneous value of EtO concentration. Why not use 5ppm over 1 minute period?

What is typically used is to employ signals from two or more detectors in order to initiate executive action. This depends on how the detectors are positioned inside your plant and what is their coverage area. If you depend on a single EtO detector in any given area, you cannot use this approach.

There is no such thing as "common sense" - Apollo RCA

RE: Toxic Gas Detector Time Delay

(OP)
Issue is false activation, even if we set it at 5 ppm over 1 ppm i will do false activation of deluge. we want to avoid it.
One more issue with the detectors that once they detect a value of 10 or 12 ppm of EtO, it will not go back to original within a min, some time in 90 Sec.

So if we put 1 min time delay for 5 ppm, it still can have activation.

RE: Toxic Gas Detector Time Delay

Activating deluge at STEL seems too conservative. Usually, we only elect to instruct operators to safely stop work and seek egress when concentrations reach STEL. Emergency escape at some higher level than STEL.
What are the other physiological effects on humans of EtO at high concentrations from which we can choose a more reasonable level for deluge activation ? What happens at the suggested 50ppmv ?

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


Resources

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