Machinery should be designed and constructed in such a way as to prevent any risk of explosion posed by the machinery itself or by gases, liquids, dust, vapours or other substances produced or used by the machinery.

Where machinery is intended for use in a potentially explosive atmosphere, it should be designed and manufactured to exclude or minimize ignition sources and comply with any national laws and standards applicable to explosive atmospheres.

"Should be" was the past, nowadays pls look at ISO 80079-36 and better to say "must be".

Keep up good work!