Below ground stationary container systems for petroleum – design and installation HSNOCOP 44 

AS/NZS 60079.10.1:2009 Explosive atmospheres - Classification of areas - Explosive gas atmospheres

CURRENT
11.5.1
Hazardous atmosphere zones must be delineated about vents in accordance with the provisions of AS/NZS 60079.10.1 2009 and any electrical equipment installed within these zones must be compatible with the zoning.
6.5
Hence, where petroleum substances are stored, hazardous atmosphere zones must be delineated in accordance with AS/NZS 60079.10.1:2009.
Appendix A: Further Guidance
AS/NZS 60079.10.1:2009 Explosive gas atmospheres Part 10.1: Classification of areas – Explosive gas atmospheres.