Eeegads... You should never ever ever ever ever
cover sensors with a plastic cup. Frankly, if there is not a proper procedure for isolation of
smoke detectors (ionisation/optical sensors are the ones you need to isolate), then I am sorry, but you should not be using atmospherics.
There are a number of different types of fires sensors - and each one is optomised for certain things (there are also hybrid sensors which contain a mixture of the lot). The four main types you will run into are Particle(Ionisation), Optical, Heat, Rate of Rise
Only two of these will be set off by atmospherics - the particle (ionisation) and optical sensors. Ionisation will detect any ionised particles caused by combusion and the other two rely on heat. Now the issue with RoR and Heat is that in a
venue with high ceilings (think
theatre) heat based sensors which are normally installed in the ceiling take a good while to go off (RoR less than Heat).
Ionisation alarms are the type normally found in homes and are prone to false alarm - most venues with decent fire prevention systems will not use these.
Basically a decent
venue will use a combination of optical and either RoR or Heat, and will have a FCP somewhere where the optical sensors can be deactivated or put into a non-alarm state of some description. If your local authority finds covered detectors, then someones head WILL
roll.