Patol’s Linear Heat Detection Cable (LHDC) has been installed in a fish processing plant in Ireland to protect the facility from any fire event occurring in the three blast freezers which are central to its operation.  The digital cable was installed in the blast freezers of Premier Fish Products, each approximately 100 square metres, where temperatures are regularly set as low as -40°C to preserve the freshly caught pelagic fish.  The cable was supplied and commissioned through the Cork office of Emerald Fire Technology, one of the leading fire detection companies in the country with considerable experience in providing fire detection solutions in industrial applications. 

Protecting its processing plant

The Patol LHDC solution is operating at the new factory of Premier Fish Products in the fishing port of Killybegs. Over the course of its thirty-four years, Premier has become one of Ireland’s leading fish processors.  By fishing off the northwest coast of Ireland, the company’s fleet of vessels is able to harvest some of the best quality fish in the world primarily from the North Atlantic Ocean. Through ownership of its own boats, the company is able to ensure continuity of supply and has direct control over the quality of its catch.  The company prides itself in maintaining the highest food safety and quality standards - and on its internal quality and specification systems which exceed those in the marketplace.  Having consistently gone to such lengths to catch and deliver its quality seafood to its worldwide customer base, the company naturally wanted to protect the products and its processing facilities, but the low temperatures of the blast freezers made special demands on any installed fire detection solution.

Early warning in harsh environments

The extremely cold temperatures of the blast freezers, coupled with the powerful airflow (which could exacerbate any ignition), proved a challenging environment with which most fire detection technologies would be unable to cope. However, digital LHDC has a minimum operating temperature of -40°C, making it ideally suited to the requirements of Premier Fish Products.  Three zones of 70°C digital LHD

cable were installed, and to ensure ease of maintenance, three end-of-line units with Fire/Fault test-facilities were located outside the freezers to enable integrity testing of the system.  The three LHDC zones are integrated into the site-wide addressable fire alarm system - also supplied and commissioned by Emerald Fire Technology - which protects the whole Killybegs site.

Patol, a global leader in the design and supply of specialist fire detection products for industrial applications, manufactures its LHDC to provide early detection of fire and overheating in circumstances where other forms of detection would not be viable - either through the inability to withstand the environment or through prohibitive costs.  It is available as non-resettable (digital) and resettable (analogue) technologies. 

Simple but effective

Comprising a twisted pair, two-core cable, the digital cable operates by reacting to heat, with each core comprising a tinned copper-coated spring steel conductor with a special, heat-reactive, polymer insulation.  The insulator between the two conductors plasticises at a pre-determined temperature creating a switch circuit at the point of operation.  The cable has a protective, chemical-resistant and UV-resistant outer sheath.  The LHDC cable is employed in conjunction with an end-of-line terminating device for continuity monitoring and a zone-monitoring controller to provide outputs for Fire and Fault.  Extra physical protection is available via optional stainless steel outer armour and a ‘Distance Location’ controller which indicates the distance to the point of operation is also available.  As digital LHDC provides a simple switched output on operation, the cable can be monitored by a conventional or analogue addressable zone monitor.