Explosionproof fittings and wet locations

[Carultch]

When conduit fittings are rated explosionproof, does this also include a rating that it is waterproof? And therefore suitable for a wet location?

How is an explosionproof fititng constructed, different from its standard fitting counterpart, in order to achieve the rating for "explosionproofness"?

My thoughts are that if a fitting can seal out the gasses related to explosions, then it should be able to seal out water.

 

[rbalex]

Explosionproof fittings are not necessarily waterproof; some are, but they are independent features.

FYI, explosionproof fittings are not vapor proof. In fact, gases are practically guaranteed to enter. (Water too) What is "proof" is an internal explosion has its temperature limited when escaping the enclosure and prevents igniting an external atmosphere.

 

[kwired]

Explosion proof fittings generally still let gas pass through threads or machined surfaces, in particular heated gas under pressure from an explosion that occurred within. The idea is those escaping gases passed through enough metal mating surfaces that those surfaces absorbed enough heat from the escaping gas that it no longer has enough heat to ignite any hazardous gas outside the enclosure/fitting.

The idea of sealing something to keep ignitable vapors out, only works for so long and you likely develop a failure in that seal.

The idea of containing the explosion, that they likely will happen at times and assuring that the escaping gases will be sufficiently cooled mostly eliminates the need for perfection in sealing, as well as less need to worry about minor deterioration of sealing and is recognized to be a better overall design.