Leakproofness testing of aerosols filled in the UK
Arrangements for the approval of alternatives to the hot water bath method.
Aerosol dispensers and small receptacles containing compressed gas (gas cartridges) which are filled, transported or placed on the market in the UK must pass a leakproofness test before they are offered for carriage. This is a requirement of both the EC Aerosol Dispensers Directive and the Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations (CDG), the latter by reference to the European Agreement on the Transport of Dangerous Goods by Road (ADR). Certain types of sterile pharmaceutical aerosols containing non-flammable gas are exempt from this requirement but these are few in number.
Both ADR and the Aerosol Dispensers Directive require leakproofness to be proved by totally immersing each aerosol or gas cartridge in a hot water bath and whilst it is held under water, inspecting it for bubbles rising from the seams or valve. The task is almost exclusively accomplished by the filler immediately after pressurisation of the receptacle. Since publication of the 2007 revision of ADR, National Competent Authorities may authorise the use of alternatives to the hot water bath method for aerosol dispensers, providing an equivalent level of safety is maintained. From 1 January 2015, these provisions extend to gas cartridges also. One alternative method, developed by the European Aerosol Federation (FEA), is described in their "Guide on Hot Water Bath Testing Alternatives", published June 2008. Practical trials have demonstrated that the integrated test and quality assurance system set out in that guide, when properly implemented, is capable of meeting the relevant requirements of ADR (1).
The Dangerous Goods Division of the Department for Transport (DfT) performs the functions of the Competent Authority for the United Kingdom on behalf of the Secretary of State for Transport. The Department has established procedures to authorise aerosol and gas cartridge fillers to operate an alternative leakproofness test system, in accordance with the requirements of ADR, should they so require. The authorisation programme is operated by the VCA Dangerous Goods Office (VCA), an executive agency of the DfT.
Companies seeking authorisation to use an alternative leakproofness test method in the UK are strongly advised to implement a quality assurance system meeting the requirements of Annex C of the FEA guide, since this method has already been validated. Other equally effective systems may be considered, but before any could be approved, a comprehensive technical validation programme will be required to demonstrate parity with the hot water bath method. This is likely to be far more costly and time-consuming than implementing the FEA system.
Normally, when the FEA guidance is followed it is only necessary to ascertain that the applicant's implementation of it incorporates the essential features and that its operation is managed effectively. Authorisation may then be granted for the use of individually identifiable leakproofness test systems and specified filling lines, subject to satisfactory initial and periodic audits of the quality system. Audits will normally be performed by VCA or auditors approved by them.
The Dossier of Evidence will be reviewed and, if satisfactory, VCA will arrange to audit the applicant's filling operation and management system for which an audit fee is payable. The costs involved will depend upon the scope, scale and location of the operation to be audited and an estimate will be provided before the audit appointment is confirmed.
If the Dossier of Evidence, or the processes it describes, is deficient in any way, an audit will not be offered. Instead, VCA will inform the applicant of any areas that appear to require attention before an audit can take place. To ensure impartiality, VCA cannot offer the applicant any more than general guidance on corrective actions. If technical assistance with the rectification of deficiencies is required, it must be sought elsewhere. Once the applicant believes all of the issues have been adequately addressed, the dossier may be resubmitted to VCA, who may make an additional charge if significant work is involved in re-evaluating it. An audit will be offered when the dossier is considered adequate.
At the initial audit the major aspects of the quality system will be scrutinised, including, but not limited to:
If the system fails to meet the requirements of the guidance or regulations, or it is found not to be operating in accordance with procedures, the auditor will issue a notice of non-compliance(s) which the company must address before authorisation will be considered. In many cases, written evidence of the rectification of non-compliances will be accepted, but occasionally a supplementary site audit may be necessary, and this will incur additional cost.
When the system is considered to meet the requirements of the guidance and regulations in full, the auditor will submit a report to VCA with a recommendation that authority be granted to the filler to operate that system as an alternative to the hot water bath method of leakproofness testing.
VCA will offer authorisation, subject to the company agreeing the terms and conditions of issue and if accepted, a letter of authorisation will be issued.
Authorisation may be maintained subject to the authorised system remaining effective and operating at an acceptable standard. The authorised filler must promptly notify VCA of any significant changes in equipment, procedures, location or personnel.
Authorisation may be terminated by either party for any reason, at any time, giving a minimum of 7 days written notice.
Application for approval may be made in writing to VCA at the following address:
Aerosol Leakproofness Testing
1. UN/SCETDG/24/INF.49, Presented to the Sub-Committee of Experts on the Transport of Dangerous Goods, Twenty-fourth session, Geneva, 3-10 December 2003
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