How emergency lighting saves lives

This article about emergency lighting by Mark Frary was first published in the IEC's e-tech newsletter, June 2006.

This article about emergency lighting by Mark Frary was first published in the IEC's e-tech newsletter, June 2006.

This year marks the 100th anniversary of the 1906 earthquake that destroyed much of San Francisco.

The number of deaths reported officially at the time was just under 500 but many estimate the true death toll to have been much higher, running into thousands.

While the final toll will almost certainly never be known, the fact that many of the deaths were caused by fire rather than by the initial earthquake is undisputed.

Despite the century that has passed since then and the advances in fire protection that have happened over that period, the number of people dying in fires is still high.

Around 4 000 people die each year in fires in the US, around 2 200 in Japan and several hundred in each of the UK, France, Germany and Canada.

Understandably, most of these deaths occur in residential properties.

The National Fire Protection Association in the US says that the number of deaths in non-residential fires amounts to something like a hundred.

The reason is straightforward.

Commercial buildings typically have extensive fire protection systems which are well maintained and frequently upgraded.

Companies are also required to conduct regular fire drills so that employees know what to do and how to exit the building.

This last point - getting out alive - is crucial and it is inevitable that more attention has been paid to this since the tragic events of 9/11.

One of the key elements in any commercial protection system is emergency lighting that illuminates in the event of a fire or other disaster.

This is not a small undertaking.

Large buildings might require hundreds or thousands of luminaires to illuminate escape routes and indicate emergency exits.

It is unsurprising that fire protection, including emergency lighting, can amount to a good proportion of the total cost of constructing a building - perhaps as much as ten per cent.

Emergency luminaires and associated test circuits come in three types.

The most basic is a standalone unit including its own power source and an LED indicator to show when the luminaire has a fault.

This type is practical for small applications because the initial installation costs are small and manual or automatic checking of each one is feasible.

Often this manual checking can be added to the regular duties of a night watchman.

Yet even here, the cost benefits are not necessarily clear.

Over the course of the life of a building, the costs of manual checking and battery and lamp replacement can mount up to more than fully automated systems that initially cost more.

The second type again has its own self-contained power supply but uses a remote control panel for monitoring.

Although luminaires can still be inspected manually, these systems allow for the correct functioning of the luminaries to be monitored from a central point.

The larger most sophisticated systems have a remote control panel and all the luminaires are powered from a central battery unit.

For owners of buildings and the people responsible for fire safety within them, making sure that these costly systems work when required to do so is a challenge.

As a result, regular testing is vitally important to make sure that on those relatively infrequently occasions that an emergency lighting system is called into use it fulfils its life-saving function.

IEC 62034, Automatic test systems for battery powered emergency escape lighting , goes a long way towards that goal.

The standard specifies two three types of test - a monthly short duration functional test to check that the electrical circuit is operational , a monthly short duration test of the battery and an annual full battery duration test.

The requirement for a full duration test, in which the battery is fully discharged, is a potential safety risk.

If the unit is discharged and an incident occurs shortly afterwards, the unit will not have sufficiently recharged to work properly.

As a result, it is recommended that units are tested when the risk is low, say at night when many buildings will be unoccupied.

For buildings that are permanently occupied, such as power stations , hotels and hospitals, this is not feasible.

" You can't do the annual test in one hit," says Chris Watts, project leader on the IEC 62034 standard .

"You have to test alternative luminaires".

"An automatic system can do that for you".

"If you have a failure after you have run a test, you will at least have one luminaire in each compartment fully charged; that is an acceptable way of limiting the risk." To reduce this risk, systems that use central batteries could have often have dual batteries so that one can be tested while the other can be used to operate the system in the event of an emergency, but this is very expensive.

Instead it is normally preferable to test for two thirds of capacity and analyze that the battery is performing correctly.

Among the other requirements of this recently published standard are that the system should be appropriate for the application, risks during the test should be minimized and that recharging of the system should be checked after each test.

The standard also sets out requirements for timing, to ensure that automated tests are carried out at the correct intervals.

Timers must be accurate to 75 seconds a week and must continue to function in the event of an extended power outage.

In the UK , the publication of the standard is timely.

New legislation enters into force this October that makes employers responsible not only for putting in emergency lighting but also for it to be tested properly.

This changes the responsibility from the current system under which each building has a fire certificate.

When a fire inspector carries out a regular inspection, any problems are highlighted and are expected to be remedied in time for the next inspection.

Given the number of fire deaths in the UK , the legislation is likely to be put to the test quickly after its introduction - an incident will occur where a system has not been properly tested and the employer involved will be made an example of in the courts.

The implementation of the legislation in practice is also likely to be driven by insurers who are likely to insist that a full testing regime has been carried out in order for cover to be valid.

The standard will also have application across Europe as a whole.

1989's Workplace Directive includes requirements for the use of emergency lighting.

Watts says that it will also be in use internationally".

""For example, European legislation applies to hotels that Europeans stay in on holiday so a lot of countries are aware they have to meet European safety legislation." Over the long term, properly tested automated systems are going to save both money and lives".

""End users find testing expensive and arduous," says Watts ".

""Automated systems take the drudgery out of it." As for saving lives, when the next earthquake hits San Francisco, automated systems like these will surely help mean more people live to tell the tale.

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