Ventilation Energy and Environmental Technology
                                     from VEETECH Ltd.              Updated 9th July 2008


phptoxicgas.php - The toxic gas ingress calculator to determine protection level against accidental toxic gas release

Click here for ventilation rate calculator

Written by Martin W. Liddament

Data Input Form


Building and Ventilation Details:

Volume of Space (m3)

Ventilation Rate (L/s)





For a simple background to ventilation order the Guide to Energy Efficient Ventilation

Summary: This algorithm is aimed at identifying how successfully and for how long a building can protect its occupants from an accidental release of toxic gas. A normalised concentration cloud of unity is assumed to envelope a building at time t = 0 seconds.
This calculation technique indicates the corresponding rise in concentration within the affected building.
The time taken (in hours) to reach concentrations of approximately 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.95 of the outdoor concentration is given.
The calculation is based on dilution for the given ventilation rate and building volume.
Assumptions
The indoor space is assumed to be uniformly mixed.
The pollutant cloud is assumed to be at a uniform concentration.
Caution This algorithm provides an approximate solution only. It must not form the basis of critical design or risk assessment. Results cannot be guarenteed.
Theoretical Basis: Dilution Equation given in British Standards BS5925.
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