| 1 (basic utility) | Car parkingPlant rooms (excluding electrical equipment)
 Workshops
 | Some leakages and damp areas tolerable. Local drainage may be required | > 65% normal UK external range | Visible damp patches may be acceptable | Minor seepage may be acceptable | Car parks: atmospheric Workshops: 15-29 oC Mechanical plant rooms: 32oC max. at ceiling height | 
		
			| 2 (better utility) | Workshops and Plant rooms requiring drier environment than Grade 1 storage | No water penetration but damp areas tolerable dependant on the intended use. Ventilation may be required to control condensation. | 35-50% | No visible damp patches, construction fabric to contain less than air dry moisture content. | None acceptable | Retail Storage: 15oC max. Electrical Plant rooms: 42oC max. | 
		
			| 3 (habitable) | Ventilated residential and commercial areas including offices, restaurants, and leisure centres etc. | Dry environment. No water penetration. Additional ventilation, dehumidification or air conditioning appropriate to intended use. | 40-60% 55-60% for restaurants in summer
 | None acceptable. Active measures to control internal humidity may be necessary.
 | None acceptable | Offices: 21-25oC Residential at 18-22oC Leisure Centres- Spectators: 18oC
 - Squash courts: 10oC
 - Changing rooms: 22oC
 - Swimming pools: 24-29oC
 Restaurants: 18-25oC Kitchens: 29oC max. | 
		
			| 4 (special) | Archives, Landmark buildings, and stores requiring a controlled environment | Totally dry environment. Requires ventilation, dehumidification, or air conditioning appropriate to intended use. | 50% for art storage >40% for microfilms and tapes
 35% for books
 
 | Active measures to control internal humidity probably essential | None acceptable | Art storage: 18-22oC Book archives: 13-18oC |