Installation Guidelines – TP FRTEK20 (S & E)
TP FRTEK20 cables should be installed either when both the cable temperature and the ambient temperature are above 0°C and have been so for the previous 24 hours or where special precaution have been taken to maintain the cables above this temperature.
The installation of TP FRTEK20 is very simple & intended for installation in air. It can be clipped directly to robust construction (as per BS 5839) and also suitable for use where it will be subjected to vibration or flexing hence reducing chances of cracking/failure of the cores.
Cables which are directly fixed to surface should be neatly run and securely fixed at suitable intervals.
The cables should not rely on suspended ceilings for their support.
Cables should be installed in one continuous length. Joints in the cable should be avoided. In case of unavoidable circumstances it should be within the fire resistance enclosures.
Where a cable passes through an external wall it should be contained in a smooth bore sleeve of metal or other non hygroscopic material sealed into the wall. This sleeve should slope downwards towards the outside and should be plugged with a suitable non-hardening waterproof compound to prevent the entry of rain, dust etc.
Where a cable passes through an internal wall, a small clearance hole should be provided. If additional mechanical protection is necessary a smooth bore sleeve should be sealed into the wall.
The cable support should be non combustible particularly when it is supported by plastic cable clips or cable ties & such that circuit integrity shall not be reduced below that afforded by the cable used.
Critical Comparative Study : Fire Resistance Cables conforming to
(1) BS:7846 & BS:7629-1 and (2) BS EN 60702-1
In order to achieve 2 to 3 hours fire protection rating at950°Calong with simulated fire extinguishing system, Mineral Insulated (MI) cables conforming to BS EN 60702-1 are being used. Magnesium Oxide is used as insulating material along with metal jacket in MI cable. Magnesium Oxide insulation has high affinity for moisture and if the cable comes in contact with water the insulation can become electrically weak and can cause electrical leakage from conductor to conductor and the metal sheath. Therefore, lot of care is required to be taken while terminating the cables. The construction of MI cable is complicated and therefore very expensive. In addition to the cost, experience of the Technicians / Electricians is that is difficult to install & not suitable when subjected to vibration or flexing as it can lead to cracking of the cladding & cores and finally leading to failure.
Now, withSpecial composite insulation of Silicone Rubber & Ethylene Propylene Rubber (EPR), the cables can pass the required circuit integrity test at950°Cwhich are prescribed for MI cables. No special tools or accessories are needed for installation or termination of such (CI)cables, unlike MI cables. As already mentioned above, MI cables are extremely moisture sensitive on termination and must be terminated by qualified persons only, which is a tedious and time-consuming affair.Silicone & ERP Insulatedunarmoured & armoured Fire Resistant (CI)cables conforming to BS: 7846-2009 & BS: 7629-1-2008 are designed to meet requirement of fire resistance test as perBS 5839-1:2002 + A2:2008, BS 8519:2010, BS-8491:2008, BS-8434, BS EN 50200:2006 + Annex. E & BS-6387:1994 C.W.Z.The Silicone Insulation(as per BS EN 50363 – 1 having maximum material operating temperature upto 180°C)gives hard ash when exposed to sever fire condition and possesses the Fire Resistant requirements to maintain the Circuit Integrity. In addition to maintaining Circuit Integrity during exposure to fire, these(CI)cables also produce very low levels of smoke and virtually no (less than 0.5%) acidic or toxic gases, thus safeguarding human life and protecting equipment.
It would be advisable to refer British StandardBS 5839-1:2002 + A2:2008– Fire detection and Fire alarm systems for building, page 70, section 26.2, as follows :-
“b) Cables used for all parts of the critical signal paths for the extra Low voltage supply from an external power supply unit and for the final circuit providing low voltage mains supply to the system, should comply with the recommendations of 26.2d or 26.2e and comprise one of the following :
- Mineral insulated copper sheathed cables with and overall polymeric covering, conforming to BS EN 60702-1, with terminations conforming to BS EN 60702-2.
- Cables that conform to BS 7629.
- Cables that conform to BS 7846.”
Therefore, we cannot just be restricted to MI cables as there are other cables (as per BS 7846 & BS 7629) that can be recommended in order to maintain that Circuit integrity.