Choosing the right Fire Safety Solution

Choosing the Right Fire Safety Solution

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.

To learn more about fire detection, prevention and suppression, Mr. Arindam Bhadra, Technical Consultant at SSA Integrate, answers a few questions.

1. Why should businesses consider fire detection, prevention and suppression products ?

Arindam: The outbreak of a fire could destroy a business and its property, not to mention the loss of human life. The costs of replacing everything would be incredibly high and an extremely time consuming task. One of the best ways to prevent such an extremely unfortunate or unsuccessful event is to make use of a fire alarm system.

2. What are the factors that will affect your choice of fire solution, for example, building infrastructure, number of employees etc.?

Arindam: There are essentially two types of fire alarm systems: Conventional and Addressable. A conventional system is suitable for factories with large open areas requiring detection as well as small commercial buildings. For larger buildings and installations, an addressable system is recommended.

Most insurance companies will require that your fire alarm system meets with a specified design category as defined in IS or BS or NBC 2016. It is recommended that you make National Safety Council, FSAI, NFPA registered designer individual Member (with Valid Certificate) to provide you with assistance when designing your fire system.

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

Arindam: 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 OSID system combines multi-wavelength technology with the ability to extend beam length, or utilize multiple emitters (some wireless) with a single receiver.

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.

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.

Fire suppression in occupied areas has advanced from CO2 systems as they have finally been recognized as dangerous to use in occupied areas, and Halon 1211 and 1301, which were phased out due to being recognized 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 pressurized at 150/200 bar and commonly known as Inergen.

Novec 1230 Fire Extinguishing Fluid looks likely to become the chemical agent which will eventually be recognized 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.

4. What situations and environments warrant specific technologies (if any)?

Arindam: There are certain applications that require specific equipment be used, for example kitchens require the use of heat detectors. Escape routes require the use of smoke detectors. There are also a number of risk-specific scenarios that require the use of specialized detectors such as ember detection, UV/IR flame detectors, linear heat detection and duct probes.

The environment to be protected can also determine the most appropriate detection method used when taking into account servicing and safety requirements. In areas where it would require scaffolding and working at heights to get to point detectors, especially when over busy production areas, it would be more suitable to install beam detectors.

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

Arindam: 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.

I would advise to Design installing 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.

6. Which technologies eliminating nuisence alarms in fire detection applications

Arindam: Today more than ever, there's no place for nuisance alarms in fire detection and alarm applications. No matter the building or environment being protected, nuisance alarms should by and large be considered unnecessary and unacceptable.

Here is an overview of some of the latest technologies that can be employed today to combat nuisance alarms.

Drift compensation: The build-up of dirt and dust in smoke detectors, often the result of improper maintenance, is a major cause of nuisance alarms. As dirt accumulates over time in the chamber, the detector begins to 'drift' away from its selected sensitivity. In effect, the accumulation of dirt makes a detector more sensitive. As dirt continues to accumulate, a detector drifts toward the alarm level, the threshold that must be reached to cause an alarm.

Because of increased sensitivity caused by dirt build-up, trace particles of ambient smoke, which wouldn't activate a clean detector, can set off a device which is dirty. Transient conditions - such as radio frequency interference from cellular telephones - can similarly activate a dirty detector.

Recent advances have brought building owners powerful new technological tools that enable analogue addressable systems, by evaluating environmental data and compensating for contamination, to maintain detector sensitivity and nuisance alarm immunity. Many analog systems can now provide drift compensation, which enables detectors to maintain their original sensitivity setting over time despite the accumulation of dirt in the chamber.

In those systems, the control panel is able to continuously measure, analyse and average ambient conditions in the detector chamber, and to automatically compensate for dirt accumulation. Each sensor's average value is constantly monitored as part of a software filtering process that quantifies the build up of contamination. The environmental data is used to make adjustments that maintain the desired sensitivity level by compensating for accumulated dirt and dust. The result is a significant reduction in the probability of nuisance alarms caused by shifts, either up or down, in sensor sensitivity.

In the most advanced systems, drift compensation is accomplished by moving both the zero reference and the alarm threshold proportionately , by an amount equal to the change in sensitivity resulting from the accumulation of dirt. As an example, let's take a detector with a sensitivity setting that would cause an alarm at 2.5% per foot of smoke obscuration. And let's say the build-up of dirt over time has resulted in a change in sensitivity that equals 1% per foot of smoke obscuration. With the drift compensation feature, the system automatically moves the zero reference to 1% and the alarm level to 3.5%. As a result, just as with the original setting -,it still takes 2.5% smoke obscuration to initiate an alarm.

Multiple sensitivity levels: Some advanced systems offer building owners a choice of sensitivity levels with the UL-listed range. In a system with this capability, each sensor can be individually set at the optimum sensitivity for the environment it protects. For example, in an elevator lobby or lounge area where smokers might gather - or in other areas where small amounts of smoke might normally be present - the sensor can be set at the least sensitive end of the UL window. In high-risk installations - such as computer rooms and telephone switching centres where very early warning is important - the sensors can be set at a more sensitive level of 0.5% or even 0.2%.

In both instances, the building owner can take advantage of the full range of UL-accepted sensitivity settings, closely match the sensitivity of the detector to the area it is protecting, and guard against nuisance alarms.

In systems that cannot provide multiple sensitivity levels, each detector's sensitivity setting would typically be based only on general guidelines about protection levels for different occupancies. A computer room, for example, would most likely be equipped with a "relatively more sensitive" detector than a conference room. But it would be difficult - without causing a nuisance alarm - to determine if a more sensitive detector could potentially be used in that computer room setting.

Peak value reporting: Some newer fire detection systems have the ability to provide an historical accounting that specifies how close a detector has come to its alarm point. That "peak value" analytical data is useful in customizing a system to meet the precise fire detection application in a particular area or building.

It is important to note that detectors are set at a factory default sensitivity that is appropriate for most commercial, educational and institutional environments. Peak value logging can be valuable in applications where a more precise, experience-based sensitivity setting is desirable. In those settings, peak value logging can be used to help maximise protection and minimise nuisance alarms.

Here's how it works. All sensors can be set to a sensitivity of 2.5% at installation. After a period of time, perhaps 90 days, the sensitivity can be adjusted up or down based on an analysis of how close they actually came to being in alarm during that interval. A sensor in a conference room, for example, that might have had a peak value of 1.0% smoke could have its sensitivity lowered to 3%. A sensor in a computer room, with a peak value of 1% smoke, could be having its sensitivity increased to 0.5%. Peak value logging can be an important consideration when selecting a control panel because it enables a customer – by evaluating historical data about actual environmental conditions - to set sensors at the optimum sensitivity. The resulting sensitivity settings coincide with the fire risk in the protected environment and help prevent nuisance alarms.

Multistage alarm selection: This feature takes full advantage of systems that provide multiple sensor sensitivity levels. Through control panel programming, some systems can provide multi-stage operations for each sensor. For example, the control panel may be programmed so that in one individual sensor a 2.0% level will cause a warning that prompts further investigation - while a 2.5% or 3.0% level will automatically initiate a general evacuation alarm. The multistage alarm allows time for investigation before proceeding to evacuation.

When allowed by the Authority Having Jurisdiction (AHJ), this feature can reduce unnecessary evacuations and is particularly valuable in hospitals, hotels and dormitories or in jurisdictions where there is a charge for responding to false alarms.

7. What about existing premises? Are fire products designed to be integrated with older technologies?

Arindam: 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.

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.

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.

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

Arindam: 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.

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 Total cost of ownership (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.