From: Luis A Samaniego <l-samaniego**At_Symbol_Here**NORTHWESTERN.EDU>
Subject: Re: [DCHAS-L] Ventilation calculator for chemical spills?
Date: Thu, 22 Oct 2015 15:23:29 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 3fb3100c2c394a798acf4066197570ea**At_Symbol_Here**

Here is another software program developed by EPA for AQ modeling, this program is designed for outdoor chemical exposures though.


Luis Samaniego

Sr Laboratory Safety Specialist

Northwestern University

Office for Research Safety

303 East Chicago Avenue

Ward B-106, W223

Chicago, IL 60611



From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**] On Behalf Of Stewart, James H.
Sent: Thursday, October 22, 2015 9:11 AM
Subject: Re: [DCHAS-L] Ventilation calculator for chemical spills?


The AIHA developed an Excel application for mathematical exposure modeling called IHMOD that is very easy to use. One of the models in IHMOD is the purging equation. There are also options available to calculate the generation rate, i.e., the mass per unit time of the chemical evaporating from the spill. There are sliders in IHMOD that allow you to vary the ventilation rate and/or the generation rate (size of the spill) and see the impact of the change. The application is free. IHMOD can be downloaded at the following link:

Jim Stewart

Past Chair of the Exposure Assessment Strategies Committee, AIHA


James H. Stewart, Ph.D., C.I.H., CSP

Instructor on Occupational Hygiene

Harvard School of Public Health

Exposure, Epidemiology and Risk Program

Landmark Center 4th Floor

Boston, MA  02115



From: DCHAS-L Discussion List <dchas-l**At_Symbol_Here**> on behalf of Boitumelo Kgarebe <bkgarebe**At_Symbol_Here**GMAIL.COM>
Sent: Thursday, October 22, 2015 3:48 AM
Subject: Re: [DCHAS-L] Ventilation calculator for chemical spills?



Can anyone pls assist me urgently. I head an Occupational Health Analytical Laboratory facility in Johannesburg. We are about to take over a newly renovated organic chemistry lab. An emergency shower has been installed, but with no drainage. We are being told that that is the norm in South Africa.


Apparently, the General Safety Regulations framed under the OHS Act, Regulation 3 (9) states that “Where an employee at a workplace is exposed or can be exposed to a potential hazard of injury to or absorption through the skin as a result of sudden contact with a large amount of toxic, corrosive, high risk or similar hazardous substance, the employer concerned shall make sure that there is a fast-reacting deluge-shower with clean water or a similar facility in the immediate vicinity of the workplace of such employee and that the employee is trained in the use thereof.” There is no definition of large amount and again no reference to drainage to sewer (or otherwise).

I disagree since this would mean that in the event (hopefully rare) of an accident, an employee will wash off the contaminant and still "stand" in the contaminated water. How are your emergency showers configured?



Boitumelo Kgarebe

National Institute for Occupational Health

Johannesburg, South Africa 


On Tue, Oct 20, 2015 at 8:50 PM, Secretary, ACS Division of Chemical Health and Safety <secretary**At_Symbol_Here**> wrote:

From: Mary.Biersack**At_Symbol_Here**

I am looking for a good industrial hygiene resource for calculating the evaporation rates of a spilled chemical and the amount of ventilation required to keep the chemical spill below the specific chemicals OSHA PEL (ppm).  Does anyone know of any good computer software programs or calculators?


Mary Biersack
Lab Safety and Chemical Hygiene Specialist
West Pharmaceutical Services, Inc.
+1 610-594-3278
530 Herman O. West Drive | Exton, PA 19341 | United States

Find West on Twitter and LinkedIn.

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