So we shall consider it.
An interesting case is the reflection of wall glasses / windows / doors with glasses in industrial units of potential hazardous area industries. If there is any abnormal condition, you shall assess it as per the probability of a potential ignition source.
Yes, light can be a potential ignition source. You might remember Robinson Crusoe from Defoe first published back in 1715.
Robinson managed to do it, so we may live the consequences as well.
Keep up good work!
Arpad
The preliminary examination for occupational safety – except in the case of hazardous technology – may be conducted by a person with specialized training and professional qualifications in occupational safety, a person authorized by law, or an accredited institution. The examination of hazardous technology must be conducted by a person with a professional license in occupational safety and Explosion protection.
#exprofessional
Who still believes IP67 is better than IP66? What is IP69 and
In many cases Ex certificates are not available with the product (pre)information.
Still many ask if the Ex devices shall be Ex certified or
arpadveress 
