The technicalities of fire

September 2013 Fire & Safety

The fire industry is a mixture of old and new. Many installations still use technology that was invented years ago and still does a good job of fire prevention, detection or suppression. At the same time, technology has advanced and we find newer technologies doing things we could almost not imagine possible a few years ago.

Hi-Tech Security Solutions spoke to two of the larger players in the fire market about what technologies are available today and their usefulness in managing fire threats. We spoke to Derek Waddell from Xtralis and Jim Grant from Brigit Systems.

1. How have fire detection/suppression technologies changed over the years? What are some of the latest technologies/solutions available?

Waddell: At a base level, fire detection and suppression technologies have evolved from systems designed purely to save life and structures to systems that additionally protect business continuity and livelihood. Early and Very Early Warning (VEW) systems are now prevalent because early intervention minimises loss and interruption.

Aspirating Smoke Detection (ASD) is the most commonly used of the VEW systems due to its high sensitivity, flexibility of installation, lower total cost of ownership (TCO) and the ability to integrate into business processes. The latest ASD systems provide integrated gas detection and addressability (fire location) to up to 15 points. ASD is now used in environments ranging from clean rooms to coal mines.

Beam technologies have undergone a revolution as well with new multi-wavelength technologies all but eliminating nuisance alarms that have traditionally plagued this type of detection. The Xtralis OSID system combines multi-wavelength technology with the ability to extend beam length, or utilise multiple emitters (some wireless) with a single receiver. Again the benefit is reduced TCO with minimum nuisance alarms.

Multi-criteria systems, combining detection for heat, smoke and CO, are being deployed in spot detectors to eliminate nuisance alarms from lint, steam and insects with varying degrees of success. The industry, in a sense, awaits the results of nano- and other technologies for the next generational breakthrough.

Absent the perfect fire detector, remote video verification of fire alarms is proving to be a cost-effective means of eliminating false alarm call-outs, saving first responder resources and owner/occupier fines [in countries where false-alarm callouts are fined].

Grant: The basic optical smoke and heat detectors have remained much the same as far as the principle of operation is concerned, but advancement in electronics have made them faster reacting and more reliable than their predecessors. The ionisation smoke detector, which reacted more to fast burning fires, has virtually ceased to be manufactured as the small amount of radioactive material they contained became an environmental issue. The multi-sensor detector is basically an optical smoke detector, making it react to smouldering fires and with the addition of a heat sensing element, allows it to be more sensitive to fast burning fires similar to an ionisation type.

Flame detectors have advanced from the basic UV (ultra-violet) to IR (infrared), to units that employ both UV and IR, as well as dual IR and triple IR, enabling much faster detection of fire and are less affected by the environment, e.g. solar blind, dust etc.

Photo-electric beams have advanced allowing them to be employed over longer distances and some without the use of a receiver, using a reflective plate, making the emitter both emitter and receiver. Some units also have self-alignment capabilities, which obviously makes installation of beam detection somewhat easier than before.

By far the biggest advancement in fire detection is the use of Aspirating Smoke Detection (ASD) systems. This is the most technologically advanced type of smoke detection available today and is the quickest response smoke detection.

A development of this technology is the Titanus System, manufactured in Germany by Wagner. The company has decades of experience as a manufacturer of high sensitivity air-sampling smoke detection systems. Their highly sensitive very early warning fire detection system operates during the decisive, incipient phase in fire development and is made immune to false alarms by LOGIC-SENS. This technology offers intelligent signal processing using a very high scan rate, which differentiates between environmental disturbances, such as dust or other airborne particles and gives immunity to false alarms.

The air-sampling smoke detector is capable of detecting microscopic particles of smoke, where air is drawn through a network of small-bore pipes laid out above or below a ceiling in parallel runs covering a protected area. Small holes drilled into each pipe form a matrix of holes (sampling points), providing an even distribution across the pipe network. Air samples are drawn past the highly sensitive optical device, tuned to detect the extremely small particles of combustion.

They may be used to trigger an automatic fire response, such as a gaseous fire suppression system, in high-value or mission-critical areas, such as archives or computer server rooms. The system is up to 100 times more sensitive than standard spot detection and provides multiple levels of alarm thresholds.

Fire suppression in occupied areas has advanced from CO2 systems as they have finally been recognised as dangerous to use in occupied areas, and Halon 1211 and 1301, which were phased out due to being recognised as ozone depleting products.

As in the past fire suppression systems are split into two camps, inert and chemical. The inert protagonists claim that the use of naturally occurring gases to reduce the oxygen level below that where fire can be sustained (most substances will not burn below a level of 15% volume of oxygen in an atmosphere) is more environmentally friendly than the use of chemical agents.

However, it can be argued that due to these gases being stored at high pressure typically 200/300 bar and the large number of cylinders that need to be employed for large room volumes and the process needed to manufacture these high pressure cylinders, it is more harmful to the environment than the use of chemical agents.

Amongst the inert gas systems is IG541, (52% Nitrogen, 42% Argon and 8% CO2), normally pressurised at 150/200 bar and commonly known as Inergen.

Of the chemical agents the most popular of these is HCF 227ea, commonly known as FM200. This has become a replacement for Halon 1301. However, it does have an atmospheric lifespan of some 29 years after discharge, it is an HCF and EU countries are already looking at restricting or reducing the use of HCFs.

Novec 1230 Fire Extinguishing Fluid looks likely to become the chemical agent which will eventually be recognised as the most sustainable of all the chemical agents. Manufactured by 3M, it offers a 20-year Blue Sky Warranty on Novec 1230 and guarantees to replace the cost of the Novec should it ever become necessary to replace it due to environmental issues.

2. For a greenfields office/campus/factory environment, what solutions would you advise companies to install to ensure the safety of people and assets?

Waddell: With few exceptions, good business practice would dictate that merely meeting regulations is insufficient. A very high proportion of businesses that have a significant fire event subsequently fail, even if people and the structure are saved, business disruption invariably claims its toll. For this reason it is essential that detection and suppression solutions that achieve, and most importantly maintain the required performance are preferred. For this reason an absolutely calibrated system ASD with protective design features is preferred.

Grant: I would advise companies to look at installing ASD type detection systems or at the least analogue addressable smoke detection, and the use of Novec 1230 Fire Extinguishing for the protection of any critical assets areas, such as data centres, computer rooms etc.

3. What about existing premises? Are fire products designed to be integrated with older technologies? What can risk managers do to make full use of their older fire products while keeping up with new technologies?

Waddell: In most cases a complete fire solution is a combination of active and passive measures. Building design and construction persists for the life of the building, fire alarm systems however are subject to maintenance and replacement. Key to maximising the utility of the system is to ensure that the technology used is flexible enough to adapt to changing patterns of use within a building over its life.

VESDA type ASD systems with a wide configurable range of sensitivity allows appropriate alert and alarm settings to be used as needed – from the most sensitive, to several times less sensitive than spot detectors. These systems also have the ability to integrate to legacy alarm systems on the primary reporting path, yet provide high value information both locally and remotely via other communication means.

Grant: Existing fire systems can be integrated into new fire systems, e.g. conventional type detection systems can be controlled by means of an analogue addressable system, until budgets allow for a full upgrade and replacement.

Risk managers should ensure that their systems are fully maintained and serviced at the required intervals by a reputable fire company to ensure the operational status of their equipment. Fire/evacuation drills should be conducted to ensure full operation of the system. Suppression systems should be checked on a weekly basis for pressure drop in cylinders and, if found to be the case, this should be rectified as soon as possible as the risk of one cylinder in a bank not being operational could be the difference between a fire being extinguished or not.

4. What tips would you give risk managers with respect to updating or installing new fire solutions?

Waddell: The primary role of any fire detection system is to reliably detect fires as early as possible and to do that over the life of the system for the minimum TCO. In choosing a technology, or in fact a manufacturer of a particular technology, it makes good sense to ask the prospective manufacturer to provide quantified, ideally independent data showing the performance of their product over time.

In addition consider the TCO of the system. The lowest initial capital outlay may not equate to the lowest lifetime cost for the system due to maintenance, particularly where patterns of use or other occupancy requirements change over the life of the building. Again, a manufacturer should be able to supply you with this data.

Grant: Have a reputable company inspect the system and give a full report on the age of the system and when devices need replacing (typically, smoke detectors have a life span of 10 years) and budget accordingly. They should be aware of companies who tell them that their system needs immediate replacing because one or two detectors are faulty; have the system checked out by a qualified fire inspector or reputable company.

Get advice from organisations such as the Fire Protection Association, Fire Detection Installers Association who will advise and give recommendations according to the risk involved. Avoid the use of cheap, non-compliant devices and companies who are not registered with any of the recognised associations.

Contact information

Xtralis: +27 (0)82 316 2601, www.xtralis.com

Brigit Systems: +27 (0)11 794 2217, www.brigit.co.za



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