The Directive 97/23/CE, after a 30 months transition period,has become definitively effective all over the EU since May 29,2002;consequently,all equipments whose pressure exceeds 0,5 bar have to undergo a preliminary examination in order to evaluate if they fall within the directive application range and if they have to comply with the conformity requirements and the verification and certification modalities provided for by the directive itself. In case of a positive result of such preliminary examination,the pressure equipments have to comply with the essential requirements listed in Annex 1 of the directive and must show the CE marking together with the notification number of the notified body (N.B.) involved in the production control phase (where provided for);for CSI:0497.
The Directive concerns only the input on the market of the equipments and does not deal with the operation requirements like,for instance,the periodic inspection of the safety elements (valves) which are stated by the national regulations (for Italy,by the Local Sanitary Concerns,ASL) .
The directive states for the pressure equipments and the relevant components a classification in terms of risk categories; the elements that have to be considered in order to evaluate the risk category of an equipment are as follows:
- Volume (V): the value is given in litres relatively to the inner space of the container (bulky objects net);
- Nominal dimension (DN) : nominal diameter of the pipe,given in mm;
- Maximum allowable pressure (PS): maximum pressure,given in bar,for which the equipment has been designed,according to the manufacturer’s specifications;
- Fluids: gases, liquids, vapours,pure or their mixtures.They are distinguished in two groups,Group 1(dangerous) and Group 2(not dangerous).
According to the fluids (Group 1 or 2) for which the equipment has been designed and to the result of the canculation PS x V, in case of containers and PS x DN, in case of pipes,it is possible to to define the risk category (I,II, III, IV) of the component,of the equipment or of the whole.
It is noticeable that the equipment or the whole take the maximum risk category of their components .The safety accessories are automatically classified in category IV,i.e.that of maximum risk,unless the manufacturer limits their use on specific equipments of lower category;in any case,they do not determine the category of the equipment or of the whole on which they are assembled.Besides the exclusion cases explicitly provided for by the directive,there are other situations where the pressure equipments have not to comply with the requirements of the Directive 97/23/CE: in the case of proven low limits of equipment dangerousness (as provided for in art.3,par.3 of the directive),for products under other EU directives and belonging to category I,in order to avoid a double CE marking.
Hence,should come out from the examination of the pressure equipment that it falls within the above art.3,par.3,the CE marking has not to be affixed,but rather the product has to be marketed together with the information that the customer needs in order to properly use the equipment itself.
The CE certification procedures for PED directive vary according to the risk category to which the equipments belong;such procedures recall those provided for the New Approach and the Global Approach of Decision Directives 93/465/CE which introduce for the conformity evaluation the so-called “modules”.For the components and the equipments that fall within the risk category I,the european directive admits what it is usually defined “self-certification”,i.e.the CE marking of the object on the basis of the preparation of a technical file showing that the essential requirements of the Annex I to the directive have been observed and justifying the belonging of the product to the category I,together with the CE declaration of conformity by the manufacturer and posted to the purchaser.
For the components and the equipments that fall within the risk category II the CE certification is compulsorily through a NB that will also care for the production surveillance,according to the customer’s modalities.Indeed,this second part of the CE certification called “surveillance” can be substantially performed in two ways: a) by means of a direct control of the pressure equipment production (module A1); b) by means of a control of the Company’s internal Quality system (modules D1 or E1). In this second case the NB shall ensure that the Quality system guarantees the conformity of the pressure equipment with the directive requirements relevant to it; the certificatiuon of the Company according to the ISO 9000 norms greatly assists the control by the NB.
For the components and the equipments that fall within the risk category III,the CE certification through a NB is obviously compulsory. When the manufacturer has not certfied his Quality system –design included- (module H) the carrying out of tests on the prototype to be CE certified (module B) is provided for.Such tests can be carried out according to the pertaining norms harmonizes for PED or,in case of their absence or when the manufacturer does not want to carry out them,according to other norms that the NB deems adequate to comply with the directive essential requirements.
The production surveillance can be performed through the two already seen modalities for the category II (direct control of the equipment production or control of the Company’s Quality system),also through “without notice” visits,whose frequency is a function of criticality and the non-conformities dicovered during the preceding surveillance visits.
The admitted procedures come out combining the following modules: B+ C1 ; B1 + F; B + E ; B1+ D; H.
This category is the maximum provided for pipelines.
Risk category IV requests the maximum control level of design and production; it is addressed to safety accessories and to assemblages of vessels and pipes using dangerous fluids at high pressures. For instance,category IV is never reached in case of Group 2 fluids whose vapour pressure is lower than 0,5 bar (e.g. water ar temperature lower than 110°C) whatever is the equipment dimension.
Frequent are the cases of unique assemblages (plants) i.e. designed and constructed for a specific production that will be no more repeated; in these cases the CE verification procedure of an unique product (module G) is followed; obviously the subsequent production surveillance does not take place.
For the series productions the following modules are on the contrary provided for: B+D; B+F; H1.
Products certified by CSI:
list of products certified PED (download PDF)
INFO AND ESTIMATES:
Please contact Ing. Renato Lunelli
ITALIANO