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.
