LHDC from Patol continues to offer fire protection for vital petroleum tanks

With atmospheric storage tanks used to store highly flammable products, finding an effective way to prevent what could be the catastrophic consequences of a fire is a fundamental requirement. The most common cause is worn or damaged rim seals on the floating roof of a given tank. By mounting Patol’s LHDC above the rim seal, an alert is provided should any leaked vapour ignition occur. By linking this to a suppression system, an immediate response can be triggered to any fire condition that might arise.

In this application, Patol’s 70-degree digital LHDC was selected by Mecsol, a Bristol-based company that undertakes work nationally and boasts particular experience in the hazardous area sector. The installation included a stainless steel braid around the two-core cable to provide further protection by creating an earth for any lightning strike or static electricity issues.

To allow full movement of the floating roof, a cable reeler was installed at the top of the tank, with the cable connected to the stainless-steel junction box located on the floating roof. The reeler automatically uncoils the cable when the petroleum level falls and winds in the cable when it rises, with the mechanism housed in a stainless-steel cabinet. The cable reeler is certified to IECEx and ATEX standards.

The Patol digital LHDC triggers an alarm for any hot spot occurring over a very small section of the overall cable length. While LHDC is widely used in many different applications, it's particularly suited to those with harsh environmental conditions and in hazardous areas. The cable is recognised as a ‘simple apparatus’ and connected to an intrinsically safe barrier to ensure safe operation in potentially explosive atmospheres.

Ease of routine maintenance through fire and fault testing is provided via a stainless-steel switch mounted outside the tank.

The LHDC is continuously monitored and provides open circuit (fault) and short circuit (fire) notification to a monitor located within the site’s Control Room.

Steve Wilder, technical sales engineer for the UK and Eire at Patol, commented: “This is an excellent example of how LHDC can provide a reliable and cost-effective solution for preventing fires in floating roof tanks. It's already widely adopted throughout the world and, alongside petrochemical facilities, is providing protection in applications ranging from cable tunnels and escalators through to road and rail tunnels, cold rooms and warehouse with high-rise pallet racking.”