wastewater treatment blast mitigation

huangyhg

wastewater treatment / blast mitigation
looking for a little free advice...
are wastewater treatment facilities typically designed with an eye toward blast mitigation, under the current building codes; due to the presence of methane and other potentially flammable/explosive gasses...?
thanks,
walterbrennan
i've designed many waste-water treatment plants and i've never been asked to take this into account.
in the uk we have the dsear regulations (dangerous substances and explosive atmosphere regulations).  these regulations require the designer to 'zone' areas depending on whether there are possible sources of ignition present, all the time, sometimes, feasible, etc.  a dsear risk assessment must be carried out.
these have been in force since 2000 (i think, updated 2002) and are a follow on from the old electrical zoning requirements.  the main difference is that they have now been extended to cover any source of ignition and powder/dust ignition as well as gases.  a sourceof ignition could be two pieces of metal rubbing against one another, as in a pumping station cover.  as part of the risk assessment you should try to remove the source of ignition, but it could be taken to extremes (a man with hobnail boots on a concrete floor?!?!?).
i've designed a few waste water treatment facilities and have not designed for blast forces.
design in the us is governed by aci 350.  article 8.2 mentions earth, hydrostatic, wind, earthquake, crane loads, vibration, impact, shrinkage, temperature, creep, ice, and support movement.  it also reads "consideration shall be given to the effects caused by interior pressure of the structure."  i think aci 350 would have specifically mentioned blast in the code or commentary, if the committee thought it should be designed for.
i have never designed any wastewater treatment plants for blast loading. but we do consider it may occur.  we aim to remove the risk of the explosion occuring by removing the sources of ignition at the design stage.
thanks for the response, all.
walterbrennan