| 1 (basic utility) | 
			
			 Car parking 
			Plant 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 
			 |