Explained: Simple Pressure Vessels Directive
Simple pressure vessels are intended to contain air or nitrogen at a gauge pressure greater than 0.5 bar but less than or equal to 30 bar and not intended to be exposed to heat.
They must be manufactured in series production and be of welded steel or aluminium construction with a total pressure.volume product not exceeding 10,000 bar.litres.
The Directive categorizes vessels according to their stored energy, expressed in terms of the product of maximum working pressure in bar and its capacity in litres (PS.V). Different provisions apply to each category of vessel. Category A consists of vessels whose PS.V is more than 50 bar.litres, and is divided into 3 subcategories. Category B consists of vessels whose PS.V is 50 bar.litres or less.
Although the Directive applies to the vast majority of common pressure containers designed for containing air, the scope is actually very strictly defined. Included would be most compressor receivers, but any vessel not designed for air or nitrogen or not made of ordinary steel or aluminium is automatically excluded, as are any vessels with a design pressure greater than 30 bar or over a certain size.
Products falling outside the scope of the Simple Pressure Vessels Directive will almost certainly fall within the scope of the Pressure Equipment Directive.
The Directive applies to any Simple Pressure Vessels 'placed on the market' or 'brought into service' within the EU. This means that they explicitly apply to any vessel which is sold by one company to another, or to a private user, and they also apply to any vessel which is made or imported for the manufacturer/importer's own use.
Categories of vessel
The Directive catgorises vessels according to their stored energy, expressed in terms of the product of maximum working pressure in bar and its capacity in litres (PS.V). Different provisions apply to each category of vessel.
Category A consists of vessels whose PS.V is more than 50 bar.litres, and is divided into:
Category A.1, consisting of vessels whose PS.V is more than 3,000 but not more than 10,000 bar.litres
Category A.2, consisting of vessels whose PS.V is more than 200 but not more than 3,000 bar.litres
Category A.3, consisting of vessels whose PS.V is more than 50 but not more than 200 bar.litres
Category B consists of vessels whose PS.V is 50 bar.litres or less.
Safety requirements
The safety requirements for a vessel in Category A are that:
It meets the essential safety requirements outlined in Annex 1 of the Directive
It has 'safety clearance' i.e. the successful involvement of a Notified Body
The CE marking and the other specified information is shown on the vessel
It is provided with appropriate instructions
The safety requirements for a vessel in Category B are that:
It is manufactured in accordance with engineering practice recognised as sound in an EEA State
It bears the specified inscriptions (but not the CE marking)
