Maintaining the standard

LOSS PREVENTION Standard (LPS) 1666: Requirements and Test Procedures for the LPCB Approval of Direct Low Pressure Application Fixed Fire Suppression Systems covers the requirements and test procedures for the Loss Prevention Certification Board’s (LPCB) approval of such systems using heat-sensitive pneumatic detection tubing. These systems are designed for the protection of defined volume enclosures – including electrical distribution, switchgear, control, communication and IT cabinets and any similar installations – from small local flaming fire sources.

The systems use a single method for detection and delivery of the extinguishing agent to the activation point. While electrically energised enclosures are considered the primary application for such systems, any other risk application that falls within the design criteria of the LPS can also be protected.

LPCB-approved systems are assessed for their ability to prevent fire spread between units by evaluating the effectiveness and reliability of a system to detect and extinguish the fire at its source. It’s a requirement that systems shall be capable of isolating the power to the protected enclosures and must generate a signal for an alarm.

The evaluation of a system is essentially a verification of all the parameters specified in the manufacturer’s system manual. It’s important to understand that some parameters are prescribed in the LPS and are common to all systems. However, other additional enhanced performance parameters and extinguishing agents are sometimes proposed and included by specific system manufacturers. A detailed review of a specific system approval certificate will refer to any enhanced performance features of that system.

While it’s important to acknowledge that such systems are intended solely to provide enhanced local fire protection and are not intended for use as whole room or building fire protection systems, it’s equally  important to understand the nature of the enhanced protection and the promotion of business continuity such systems can afford the end user.

Basic system parameters

LPS 1666 allows for the approval of systems under the following scenarios:

• A single system container with heat detection tube installation protecting a maximum single enclosure volume of 2 m³
• Up to four enclosures can be protected by a single system container where no single protected volume exceeds 2 m³ (each enclosure can be multi-compartment and the risk assessment must assume that only one fire will occur in any one of the enclosures/compartments at any one time)
• A maximum heat detection tube length of 10 metres from the container outlet to the end of any single detection tube run

In a world where organisations are now more reliant upon business-critical technology, the protection of equipment from any downtime, delay or destruction is vital. The ability of any business to deliver products and services to its customers requires the maximum availability of its facilities. Lengthy downtimes and interruptions can seriously impact a business’ ability to fulfil its obligations to customers. A fire scenario that’s not dealt with quickly and efficiently can exert a huge impact on business continuity.

In the same way that Data Centre infrastructure is considered critical to the digital economy, small energised electrical enclosures (including those used for distribution, control, communication and server equipment) are no less important. Risk assessments in many organisations identify fires in electrical enclosures as potential sources of severe business interruption. Specifically, electrical enclosures can present a much greater fire risk where faulty, ageing and/or contaminated equipment, damaged wiring, poor maintenance and improper installation are present. Such enclosures are often found in multiple numbers in factories, warehouses and on general commercial sites.

Historically, the fire protection of small energised enclosures has, in many instances, been an imprecise and non-certifiable area within the fire protection industry due to the lack of specific performance standards. For this reason, the default position has often been systems certified to room fire suppression standards such as EN 15004 and its international equivalents. This has been an unsatisfactory situation since the confirmation of performance when protecting small enclosures has relied on manufacturers’ own testing regimes without third party approval, the latter being deemed essential for full acceptance in the market.

With the publication of LPS 1666 in January 2017, the possibility for certification of systems protecting small energised enclosures from fire changed. It’s the promotion of business continuity by early intervention that’s really the key feature of LPS 1666 certified in-cabinet fire suppression systems.

Enhanced protection

To demonstrate the enhanced protection that LPS 1666-certified systems offer, it’s key to make a comparison between the functionality of such systems and the main historical fire suppression system solutions. Let’s take a look at the characteristics of systems certified to both EN 15004 (and its international equivalents) and LPS 1666, in turn detailing both historical limitations and the improvements now available in the protection of small energised electrical enclosures.

When focusing on engineered room fire suppression systems to EN 15004, in order to detect fire (or a high heat source) in an enclosure, the room fire suppression system will need to employ sensitive detection devices to trigger it. In well-sealed enclosures there will be very limited egress of combustion products/heat from the enclosure. Some enclosures have high IP ratings for the purposes of equipment protection. This could then lead to significant delays in detection.

Due to electrical enclosure seals, the chances of extinguishing the fire are reduced with insufficient penetration of extinguishant into the enclosure. Room suppression systems will most likely only prevent the breakout of fire from the room, but not from each individual electrical enclosure. Further, migration of fire from one enclosure to a neighbouring enclosure (or enclosures) will not be prevented.

For LPS 1666 pre-engineered systems there’s close proximity of the tube to any fire (or high heat source). Therefore, early detection is achievable. In addition, the detection regime will operate at least as efficiently within the cabinet as a much more sensitive detection device that’s positioned outside the cabinet.

Since discharge is directly into the cabinet near the fire (or high heat) source, there’s a much greater possibility that the fire will be extinguished. Discharge of extinguishant is inside the cabinet and so right at the heart of the problem. Early detection and system discharge mean that the fire is extinguished at an earlier stage in its development. This minimises equipment damage and the generation of potentially harmful combustion by-products. Just as importantly, LPS 1666-certified systems can prevent the migration of fire between cabinets

Range of tests

While fire extinguishing performance testing confirms one element of a system’s performance, LPS 1666 sets out detailed requirements for a whole range of system integrity tests and provides an assurance to specifiers and end users alike that systems are fit for purpose.

The certification of systems to LPS 1666 includes testing and confirmation of the following:

• Fire extinguishing performance based on maximum enclosure volume(s)
• A range of operation for system pressure and temperature
• Detection and activation characteristics (tube burst characteristics and proximity for actuation)
• System limits for detection tube length
• Fully installed system leak characteristics
• Maximum and minimum system temperature discharge characteristics
• System installation limits
• Full system component testing including corrosion, pressure strength, leakage, ageing and system monitoring device functionality
• Protocols for the servicing and maintenance of systems together with the approval of the manufacturer’s training programme

As previously stated, LPS 1666 certification allows inclusion within the test programme of manufacturer-specific performance proposals and system features. Enhancements included within individual manufacturers’ certifications can be categorised in two areas.

The first of these is the testing and certification of environmentally friendly clean extinguishing agents. The promotion of clean agent fire suppression is increasingly a prerequisite when considering the environmental impact of a specified system. This is – and should be – a key consideration in the specification of appropriate systems. The specification of clean agent technology will increasingly become a more prominent consideration on a global basis so it’s considered sensible to factor this into the selection of the most appropriate agent during the initial specification review.

In addition, it should be noted that the most environmentally friendly clean agent chemistries are now delivered by a variety of global manufacturing sources. While they’re nominally the same, it’s advisable to confirm the provenance of a particular system manufacturer’s certified extinguishing agent to ensure ongoing availability, consistent performance and quality when it comes to the future support of installed equipment.

Enclosure characteristics

The second area to consider is enclosure characteristics. To allow for real world conditions, system manufacturers have often identified the need to include performance assessment within the certification that confirms a system’s ability to operate with an allowance for certain enclosure features. In some adverse environmental conditions enclosures could indeed be well sealed.

In order to prevent contamination of equipment inside electrical enclosures, though, particular environmental conditions dictate the need for vents (ie openings) and airflow (ie fans) for cooling purposes. In such cases, compensation for any loss of agent should be an integral part of the system testing and certification programme.

Where such testing is transacted and enhanced certification achieved, full details will be included within the published certification. This provision in LPS 1666 may also future-proof system performance against maintenance/modifications that introduce vents and fans to an enclosure at any point in the future. This issue should be included in the consideration and selection of any specific system.

The benefits of specifying and using LPS 1666-certified systems to protect electrical enclosures are many and varied. Used in support of larger room fire suppression systems, LPS 1666 systems may serve to prevent expensive discharge events from larger systems due to early intervention. Individual system pressure switches can enable very targeted safeguarding actions including the de-energisation of selected power supplies.

There will be reduced equipment downtime, operational disruption and minimised clean up (assuming the use of a gaseous extinguishant) as a result of system discharge. There’s also a relatively low cost involved for initial system install, ongoing service/maintenance and re-filling (given the smaller capacity system cylinders for targeted protection).

Importantly, systems certified to LPS 1666 have confirmed performance as per the details and system features outlined in the LPS and the manufacturer’s system manual. Often, this is complemented by additional and separate third party certifications available for certain system components. Of particular importance is the detection tube. For that very reason, the detection tube is often supported by, for instance, UL Component Listings confirming an enhanced level of component performance.

Not only is LPS 1666 an emerging standard, but it’s also one increasingly recognised by the world’s leading insurance companies. That fact alone is one well worth bearing in mind.

Craig Halford is Managing Director of Jactone Products Ltd and Chair of the Fire Industry Association’s Extinguishing Council (www.jactone.com)