Duct smoke detectors
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27 July 2016
In response to the recent publication of BS EN 54-27 for Duct Smoke Detectors DSD, the FIA Code of Practice (CoP) for Duct Smoke Detectors (DSD) is being revised.
When it was first published (in March 2012) the CoP recommended (in clause 9.1) that DSD should be approved to BS EN 54-27 in anticipation it would be published within 6 months. It was finally approved for publication by CEN in January 2015 with a date of withdrawal for conflicting standard of March 2019 (48 months).
There have been several issues with the standard – most notably with the leakage test which was modified at the 11th hour to allow the test to be conducted with the cable entries blocked.
This was necessary to avoid unnecessary withdrawal of existing products on the European Market which might fail the new onerous leakage test while being functionally acceptable for the application.
In view of this the UK opted to include a National Foreword to the BS EN version stating:
Clause 5.6.6 of this standard defines a non-operational leakage test method using under pressures - in excess of those observed in most ducts. However, in order to pass the test it is allowed to block the cable entries - thus excluding them from the leakage test. In some devices leakage through the cable entries may adversely affect the detector's sensitivity to smoke. Users are advised to consider the potential negative effects of leakage through the cable entries before deploying products approved to this standard.
Furthermore the UK is supporting and participating in a project to revise the standard to address this anomaly.
As noted above, the new product standard requires (in the Foreword) that any conflicting national standards are withdrawn by March 2019. As there are no conflicting product standards for DSD in the UK it may be considered that the current situation (being a null position) remains in force until the new product standard becomes enforceable under the Construction Products Regulation (CPR).
This is because it would be unreasonable to enforce a new standard immediately upon publication without allowing for a transition period from the established norm in any particular member state.
It should be noted that as of July 2016, EN 54-27 has not been published in the Official Journal of the EU (OJEU ) and thus the formal “date of end of co-existence" is unknown.
Publication in the OJ has been hampered by insistence from the European commission that reference to radio-active material should be removed from the scope. An amendment to do this has been actioned by TC72 WG21 which is currently out for voting. If, as anticipated, the amended standard is cited in the OJEU then the “date of end of co-existence” will, most likely, be after March 2019. However this cannot be depended upon and a short 12 month period of co-existence may be implemented.
During this transition period the FIA CoP still recommends that a DSD carries an approval but it has been clarified that the approval may be restricted to the important elements of the DSD – such as an approval to EN 54-7 for any point smoke detector within the device or approval to EN 54-20 for an ASD type DSD.