12 Jan Fixings command equal diligence
We all know how vital it is that electrical cables meet the correct criteria for all construction projects. Now Jonathan Rawlinson, Technical Manager of Prysmian UK takes a look at the importance of reducing the risk in building design with fire resistant cable fixings.
Lives and property can depend on fire resistant cable and accessories performing as expected in the event of fire. So, ensuring that cables purchased and installed meet the correct criteria of building projects is of paramount importance and will play a major role in the process of reducing the risk in final building design.
Considering the Middle East is renowned for its impressive skyscrapers which can accommodate tens of thousands of people, in some of the world’s most affluent regions, ensuring their safety is hugely important. Selection of the correct cable, not forgetting the correct fixings, will help reduce the risk in these magnificent structures and maintain the safety of the public in the event of an emergency.
The failure of a fire resistant cable, for example, could be due to inadequate fixings of a lower fire performance rating being used, which causes damage to the cable which then ceases functioning. Cable accessories may seem a minor issue in electrical systems specification but they require adequate planning, careful selection and diligent inspection, just as the cable itself does.
As a general rule, fire resistant cables should be fixed with standard metal – copper, stainless steel or galvanised cast iron – fixings such as Prysmian group’s BICON® range1. Note that aluminium is not a suitable material for these fixings because of its relatively low melting point.
Fortunately, clear guidance exists on which cables to use for emergency, detection and life safety systems and exactly how to attach them, via British Standards. We always advise customers to focus on the documentation behind any manufacturer’s claims. All BICON® accessories are manufactured to British, European and international Standards. These are:
- BS EN 62444:2013 Cable glands for electrical installations
- BS EN 61238-1 Compression and mechanical connectors for power cable
- BS EN 61914 Cable cleats for electrical installations
- BS EN 50393 Low voltage joints
Further to this, it is recommended that cable fixings and fixing centres should meet similar testing requirements to the cable in order to ensure circuit integrity. Category 1, 2 and 3 refer to the test requirements of the cable specifically; however BS 8519 recommends that cable accessories used in life-safety systems test comparably to the requirements laid out in these categories.
Product testing to ensure these standards are met should be rigorous and regular with tests being repeated on a regular cycle. Every aspect of the cable accessory will be tested and, provided the tests are carried out by test laboratories that have themselves been certified, will uncover manufacturing issues that may compromise the performance of the product and, in effect, of the entire cable installation.
Common causes of products failing test procedures relate to the materials used in manufacture. Recycled metals and plastics that are weak, and unreliable, or plastics that may contain known carcinogens or low smoke materials that do not perform adequately when in a fire are all issues we have found in the market. Another issue of concern is incorrect product marking that can mislead the purchaser and result in the final installation being inadequate compared to the original specifications.
Surprisingly, there are a number of products and fixing solutions out on the Middle Eastern market that are untried, untested and non-certified. Some are actually non-compliant as they infringe the standard criteria and are liable to instantly fail in an emergency and result in human injury. Why isn’t this usage being stopped?
In a global market it is always possible to source low cost products that appear to meet accepted international standards. In some cases it can be difficult to differentiate a high quality product from a substandard option.
Shouldn’t best practice be application of certified, engineered fire safety systems every time wherever and whenever it is possible over price? Simply listing and continuously testing certified products eliminates all doubt.
It is not unknown for manufacturers to claim conformance with a standard without having the test data to back up their claims. An important part of the specification process is therefore to ask questions to probe the strength of any manufacturer’s claims. They should be able to provide test certificates and identify the independent testing procedures that have been carried out over time.
It is also not unknown for manufacturers to cite other standards as proof of the performance of the accessory, so it really is important to know what standards relate specifically to the individual accessory type and application.
Being able to point to historical test data is another indication of a secure track record of quality production and rigorous product testing – in some cases going back through previous brand identities.
As a cable system provider of both cables and fixings, Prysmian Group recognises that the performance of any installation relies just as much on the quality of the lower value accessory as of the cable.
The BICON product range is the result of over 100 years of cable accessory development and quality engineering, started by BICC and continued in the 21st century by Prysmian Cable and Systems Ltd, UK. The BICC1 name no longer
has any association with the Prysmian Group or its range of cable accessories.
1 The BICC name no longer has any association with the Prysmian Group or its range of cable accessories.