Ventilation: Purge Time Calculation

Calculating the time required to ventilate a contaminated space prior to entry. This video is part of the Industrial Hygiene Management class at Northeastern State University (NSU) in Tahlequah, Oklahoma. NSU's Environmental, Health, and Safety Management (EHSM) program has been recognized by the Board of Certified Safety Professionals (BCSP) as a Qualified Academic Program (QAP). Graduates of the EHSM program may apply for the Graduate Safety Practitioner (GSP) designation. For additional information contact program coordinator, Dr. Doug Martin at [e-mail]. The presenter is Dr. Doug Martin. Dr. Martin earned his Ph.D. from Oklahoma State University and is a CSP. In addition Dr. Martin worked as a safety manager in the construction industry for 20 years.

[@apoorvchoudhary774]

Thanks for this wonderful information. May I know in which code or standard we could find the reference of this formula please

[@gonzlycurgus]

Okay thank you i Already Understand, so we must converted 0.05 to Ln formula, so will get a -2.996

[@jvvee856]

Hi I love your video. thanks for this

[@gonzlycurgus]

How you get -2.996?

[@muhammadwaheedabbasi4926]

The ventilation rate inside the confined space including the ventilation rate in the breathing zone shall be plz answer

[@NoorMohammed100]

What is the Natural Logarithm value?

[@SafetyProCalculations]

The natural logarithm lnx is the logarithm having base e, where e=2.718281828....

[@tonydelpilar]

hello, I've been searching the web everywhere for a simple question regarding forced ventilation times of confined spaces but I can't find anything, not even on the Osha website. All osha said was that they recommend 20 air exchanges per hour or 3 air exchanges per minute. Any input would be appreciated!
It's for school, and the question is as follows: How long should confined a space be force ventilated if its found to be a hazardous atmosphere? A) 5 mins B) 10 mins C) 15 mins D) 20 mins

[@SafetyProCalculations]

Sorry for late reply. I don't like this question. There is really not a set time for ventilating a contaminated space. You test the atmosphere before entry. If contaminants are present you ventilate. After ventilation begins you conduct periodic testing--throughout the duration of the work operation. You ventilate until the contaminant concentration is reduced to a safe level. If the source of the contamination is in the confined space, ventilation would continue throughout the work operation.

[@SafetyProCalculations]

There is one "rule of thumb," I don't think it is a regulation, that suggests ventilating the space for 10 minutes before initial atmospheric testing.
If space is contaminated. ventilate for 10 minutes, then test the atmosphere. But there are so many more variables to consider than just time.--volume of the space, volume of ventilation air etc.
Maybe this is what the instructor is asking about?

[@balakrishnan7081]

Hi

[@SafetyProCalculations]

Hello