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Emergency Lighting and Safety Services webinar questions and answers

This webinar was arranged by the IET’s Electrician EngTech programme in association with Wiring Matters. Electrician EngTech helps electricians gain recognition of their professional competence.

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Your questions answered.

Can the Scottish equivalent to RRO be specified?

Yes in Scotland the Fire (Scotland) Act 2005 is relevant and in Northern Ireland the Fire and Rescue (NI) Order 2006 is applicable. Both of these documents cover the same principles as the Regulatory Reform (Fire Safety) Order 2005. You will observe that the principles and requirements for emergency lighting and the majority of other fire safety systems are similar to those in the documents for England and Wales.

Is it a requirement for running man signs to be back lit, or can they be a standard sign with an emergency light adjacent to the sign?

The use of internally illuminated directional signs are preferred, even though externally illuminated signs are permitted. This is due to the internally illuminated sign being more prominent and why the viewing distances half when externally lit signs are used. When we use externally lit signs, a minimum of 100 lx should be provided during normal lighting and 5 lx during an emergency. (Refer to BS 5499-4 Clause 5.2, 5.3).

Does BS 5266 Part 1 refer out to the other standards you mentioned at the appropriate points in the text?

Yes BS 5266 has many references to other standards such as BSEN 1838,BSEN 50172 and BS 7671. A designer would need access to these standards.

What is the best way to identify High Risk Areas in a building? 5266 refers to 1838 but neither identify specific areas of High Risk to be considered.

This would come from the fire risk assessment. Such things as chemical processes and fuel or gas storage areas.

If a building has a standby generator to back up the whole site in the event on mains failure does this have any influence on the emergency lighting requirements?

A standby generator may be used to back up usually safety services only but could back up the whole site. Generators have usually a 15 second start up time so may not meet a 5s time for emergency lighting.

Is there a standard to state which way a self contained emergency lighting system should be wired? I've seen it wired with a standard LN&E method so when in test all lighting disconnects putting the building into darkness, and I've seen it wired with a L.SL,N&E so standard lighting can be maintained during a interim test. Is there a standard or is it spec compliant or good practice?

There are a number of methods that can be used and this depends on the nature of the job, therefore there is no specific right or wrong way. If we look at Clause 8.3.3 of BS5266-1 (Test facility) it states, 'The test device should not interrupt power to any other electrical equipment that could cause a hazard'. In practice if the switch isolates all the lights on the circuit, you should have sufficient light from the emergency lighting, and this method ensures that the emergency lights are reinstated upon completion of the test, however the test would have to be undertaken at a suitable time, perhaps out of hours. If the switch only isolates the emergency lights of the associated circuit, the test could be done at most time intervals. However this method often results in the emergency lights being left off, therefore the batteries are fully discharged in the event of an emergency. (if latter method is used, its good practice to install a neon light to the key switch, to indicate its position. This method used to form part of the AM2 practical exam for electricians).

Why are NiCAD batteries the most common choice for self-contained emergency lighting luminaires rather than more modern technologies, such as NiMH, which might be expected to have less environmental impact?

We have approached many manufacturers, and the general reasoning is cost vs performance. NiCAD batteries are currently one of the most cost-effective chemistries on the market and very robust. However there are pros and cons between each chemistry of battery used, so the manufacturer will select the correct battery for their product. It is important that during any maintenance regime, that the batteries are replaced using the correct type, in line with manufacturers' requirements.

I note you mentioned treatment rooms but Appendix E is informative - how does that sit in the requirements especially if 50lx is difficult to achieve in 0.5s when there is safety lighting in place in a hospital?

To achieve the requirement a UPS would be fitted with dual source lighting see BS 7671 Section 710 and HTMI o6-01.

If the approved light fittings listed on the emergency lighting specification is not used by the contractor and they decide to choose alternative emergency light fittings from another lighting manufacturer on grounds of cost, is it their responsibility to obtain written confirmation from the manufacturer hat their product confirm to the necessary requirements?

The designer is the design authority for the installation. If the contractor does not follow the design they would become the design authority and take on that liability and have to comply with the standards. There may also be contractual implications.

I occasionally fit a battery backed light near the the consumer unit so that it illuminates after a power failure - to assist the homeowner. This isn't 'emergency lighting' but should I be following the same rules and consider it such?

A good idea even without a fire strategy for the building. Anything you fit must comply with the relevant standards.

Flick Test? So are you recommending key switch isolation for 15 minutes ?

If we refer to BS EN 50172 Clause 7.2.3 (Monthly) the NOTE states 'The period of simulated failure should be sufficient for the purpose of this clause whilst minimising damage to the system components e.g. lamps'. We therefore need to check with the manufacturer of the luminaires to verify this, and in practice this value is around 15 mins, therefore not as the term flick test suggests. Its important that this time is sufficient for the particular site and luminaires fitted. We also have to consider if the building may be subjected to extended periods of power outages, than the luminaire is designed for (i.e. annual black building test), as deep discharge can permanently damage the batteries. Again consultation with the manufacturer would be required. BS5266-1 Clause 8.3.3 (Test facility) repeats this for clarity.

When it's intended to have a deviation from the requirements of emergency lighting standards, what conditions are attached to this, in terms of the level of safety provided?

The emergency lighting standards including BS 5266-1 are guides to good practice for standardized applications, therefore a particular site may have a valid reason for deviating from the standards. We need to remember that compliance with the standards, will deem to comply with your legal obligations, therefore the reasoning must demonstrate that the safety of the building will not be impaired by this, and should be documented in the associated risk assessment. All relevant parties must be notified and the details must be recorded in the completion certificate.

With regards to Healthcare facilities is BS 5266 supplemented by Health Technical Memorandums?

Yes. Various organisations have additional requirements over and above British Standards which are the minimum standard for compliance.

In relation to "Responsible Person", who would normally be the person at a local authority? Fire Risk Officer, Electrical Engineer, General Manager for Housing/Non-Housing assets?

We would say the council should appoint an RP for one or more of their buildings. They should be trained, assessed and competent to carry out their duties and provided with the authority and means to discharge their duties.

Can you supply emergency light from an ATS in line with BS 8519?

Yes but it's unusual. It would need to comply with the fire strategy for the building and British Standards.

As mentioned, there are many many many Standards out there. When designing installation, does the designer need to comply with ALL the Standards, or does the designer need to choose a Standard then apply and comply with that chosen Standard only?

The design and installation should meet the requirements for the fire strategy for the building. You cannot "pick and mix" standards for economic reasons. If you deviate from standards as the design authority you would have to declare and justify the deviation.

If this subject is so important, then why do most of the BS standards cost so much?

Yes a lot of standards are expensive but can be sourced from public libraries. They are "essential tools" for a design office and a business expense.

Can you wire centrally backed UPS multiple emergency lighting ccts within the same compartment in a multi compartmented trunking? Can other life safety services share the same compartment? All fire rated singles of course...

BS5266-1 states within Clause 8.2.6 (Segregation) The wiring of emergency lighting installations should be exclusive to the installation and separate from the wiring of any other circuits. This is in order to avoid the risk of mechanical damage to the emergency lighting cables. Where cables for emergency lighting circuits are installed in a common containment system such as trunking, ducting, cable basket or cable tray as you have suggested, this is fine, but they should not be shared with any other services unless they are segregated from each other by a partition meeting the requirements of this Clause (i.e. same base material as the common containment system, is rigid, mechanically strong, and continuous, without perforation and the same height as the sides of the common containment system).

You both have mentioned, Fire Architects, Fire Engineer, Risk Assessments and Evacuation plans, how should these be incorporated into a design?

Fire safety systems should be designed by those having competence in fire engineering, therefore a consultation process is required by all the relevant persons, for each service required.

Our site is large with a lot of stand alone buildings. We use signs directive signage. If a new building is built, will signs directive signage have to be used or can we use ISO 16069 signs, as I know you are not to mix signage, is that per building or per site though?

The Health and Safety (safety signs and signals) Regulations 1996 gives guidance in their L64 document. They recommend that mixed formats should not be used, to minimise confusion. If you have more than one building with different formats (in the different buildings), I would seek advice from your health and safety advisor, or those responsible for undertaking the risk assessments onsite. The fire authority is the enforcing authority and in cases of doubt they should be consulted. One of the key differences between formats is the directional arrow, as the Europic format arrow has no meaning on the direction of travel (i.e. the arrow points down for routes straight ahead), whereas the ISO7010 format does (please refer to BS5499-4 for guidance).

Should the onus not be on the equipment supplier to fit surge protection within his panel as he is best placed to understand the vulnerability of his chosen components?

Some may do. However an overvoltage strategy would be needed for the whole building.

Please can you clarify the type of fire resistance cable - I though we now had to use FP600 not FP400?

BS 8519:2020 refers you to the recommendations of both BS9999 and BS9991 of which should be implemented, with regard to the design and installation of the electrical infrastructure for life safety and fire-fighting equipment. Three fire survival times are described in BS8519, in relation to the specific life safety and/or fire-fighting application. These are, Category 1 - 30 minute fire survival time, Category 2 - 60 minute fire survival time and Category 3 - 120 minute fire survival time. FP600 cable meets these requirements. We would always advise that you speak to the cable manufacturer on any fire engineering project, as their performances may differ between them.

I note that John stated that the ATS should be as close to the equipment as possible, but shouldn't it be noted that, for life safety systems, the ATS should be in the same fire compartment as the equipment it is supplying?

Its not always possible or practical to locate the ATS Panel in the same room as the equipment its supplying, therefore to ensure we design the most resilient system, this should be located as close as possible. During the concept design, the location of equipment should form part of the design process.

If the ATS is in the same fire enclosure as the equipment it is feeding why does the interconnecting cable need to be fire rated? Most likely your equipment is not fire resistant i.e. like your sprinkler pumps in the presentation example.

All the cables supplying safety services must be fire resistant including control wiring.

Can't the primary and secondary cable be run in separate a 2 hour fire compartment away from all other services without using fire rated cables?

If we refer to Clause 11 of BS 8519 it states 'The cables selected for life safety and fire-fighting systems should be either: a) fire-resistant cables meeting the minimum fire survival time categories for the appropriate application as shown in Table 1; or b) non-fire-resistant HV cables, having protection as described in Clause 12'. So assuming that you are talking about LV cabling, this would need to be fire rated. Its also worth looking at the note below this requirement that states 'The authorities having jurisdiction in the area of construction might specify a particular category to satisfy the requirements of the structure in its location'. This is often the case where the highest category is specified, to provide the highest level of integrity.

Sprinkler pumps are very difficult to provide supplies to via generator.

The correct selection of a generator is paramount, to ensure that the life safety load is suitably supplied and protected. It's important that general rule of thumb methods often adopted in other applications are not used, and manufacturers are consulted in all instances. Where a UPS system is used to ensure that a seamless supply is provided to the load, its important to recognise that generators typically do not like a highly capacitive load, therefore consultation between each manufacturer would be required to ensure we obtain compatibility between them.

Suppose the cables (Primary and secondary) run into a large space (car park). What is the minimum distance between them?

The objective is that the primary and secondary supplies are separated from each other so that a failure in a cable or equipment, either by mechanical breakdown or damage by fire, in either supply does not affect the other supply. A fundamental principle of BS 8519 is that both the supplies should be protected against fire and water damage and separated from each other by adopting diverse cable routes.

If you refer to Clause 7 of BS 8519, it states, When designing diverse cable routes, account should be taken of any fire risks located within the area of the cable route. Where the diverse routes come together in the same area, they should be separated from each other by a partition with a fire resistance period of at least the fire survival time identified in Clause 5 for the appropriate system and type of building. Therefore no two buildings are the same, so the minimum distances should reflect the requirement above.

Can fire pumps be directly fed without fuse protection?

No you still need to provide short circuit and fault protection see BS 7671 Regulation 560.6.9 and for selectivity.

Is it necessary to use fire resistance cable for primary supply?

Yes, the resilience and integrity of the primary supply is just as important as the secondary. BS 8519 states, The primary and secondary power sources, electrical distribution board, cables and control equipment supplying power to the life safety and fire-fighting equipment should be protected against fire and water damage for a period of at least the fire survival time identified in Clause 5 for the appropriate system and type of building. This is often found to be missed during construction, as the design process has not been followed correctly. Please refer to BS 9999, BS 9991 and BS 9997.

Question on testing - operating a school for a number of years based on a RA of the school operations and hours of use and no sleeping the annual test was reduced to 1 hour - is this still valid?

It would depend on the fire strategy for the building. That would defined escape times and equipment survival times.

We have on several projects been allowed to use the single DNO supply to feed the LSS panel separated by 60 minutes to the main panel. This avoids the requirement for the Generator. Approved by the Fire Engineer.

Unusual but the DNO would need to confirm compliance with BS 7671 Regulation 560.6.4.

Does the safety light standards specify the kind of light in manufacturing areas where flickering can cause serious injuries (ie. rotating machines like sawmills)? 

Yes stroboscopic effect may lead to unsafe situations in workplaces using rotating machinery. If the frequency of rotating machinery coincides with the frequency (or multiples of the frequency of the light modulation) the machinery can appear to be stationary, therefore leading to a potentially hazardous situation. Historically because of the illusion that the stroboscopic effect can give to moving machinery, especially with the use of fluorescent lighting, it is advised that single-phase lighting is avoided. Modern LED lighting can also produce a flicker or stroboscopic effect, but the fact that it relies on a direct current to operate instead of an alternating current makes the chances of it happening less likely. In all instances the manufacturer would be able to advise on this, when designing all means of lighting, not just safety or emergency lighting schemes. This should be assessed within the risk assessment for the premise.

For primary and secondary essential power services is it suitable for each of the power supplies to run in separate cable tray within the same corridor?The guidelines state they must run in separate routes but does that solely relate to them not running in the same cable tray/riser?

No unless you can clad the cables in fire rated enclosures to provide the fire separation, usually 2 hours.

On a small communal flat hallway with 1 flight of stairs and 1 entrance/exit. How detailed would the log book need to be and what information would need to be provided?

The format of the logbook should be inline with BS EN 50172 (Clause 6.3 Log book [Reporting]). For a simple emergency lighting scheme such as this, it requires the same basic information as a complex system would.

This would include:

a) date of commissioning of the system including any certificate relating to alterations;

b) date of each periodic inspection and test;

c) date and brief details of each service, inspection or test carried out;

d) dates and brief details of any defects and of remedial action taken;

e) date and brief details of any alteration to the emergency lighting installation;

f) if any automatic testing device is employed, the main characteristic and the mode of operation of that device shall be described.

Is there an easy guide to determine the emergency safety signs to be used, i.e. arrow up or arrow down etc.?

Please refer to BS5499-4 as this illustrates the signage in a very easy to understand format, with pictures and example layouts of premises.

Would a fire alarm require an SPD?

Life safety equipment requires protection by surge protection devices and forms part of the risk assessment process. If you refer to BS EN 62305, during the risk assessment the reduction factor can only be ticked if there is surge protection fitted to the alarm circuit. Manufacturers also require these to be fitted to their products in most instances.

With SPD devices, will a type 1 be sufficient or should it be type 2?

This would form part of the risk assessment process within BS EN 62305. No two buildings are alike, therefore a site assessment would be required. Please seek guidance from your LPS service provider.

Central battery systems used in large areas during the monthly test inspections of the luminaires can take up to 45 minutes can this have a detrimental effect on batteries?

Assuming the CBU is certified to BS EN 50171 and the correct batteries are fitted (10 year design life) then a monthly discharge of 45min should be fine (this should have formed part of the design, knowing the length of time it would have taken to test). Its imperative that the temperature of the batteries is maintained at 20 degrees for optimum performance, and that the manufacturers service schedules are maintained (Generally 6 monthly). In higher risk installation such as airports, it is recommended that a battery monitoring system is installed (with ohmic measurements) to continually check the performance of each cell, if this function is not part of the CBU itself.

Is there any work going into making all these regulations more easy to understand and follow. We are in digital age, we expect things to be easy to follow.

The British Standards in particular BS 5266-1 2016, have been written in a concise way, so they are easy to understand and cross reference.

The IET offer a number of guidance documents in a digital format, which are easy to navigate from a PC, tablet or mobile phone. Most Standards are available to view from numerous bodies online (including some local libraries) in PDF format which again can be used on most mobile devices.

Regarding SPDs in domestic dwellings, can a contractor using the risk assessment method decide not required. however, we have life safety services i.e. smoke detectors in dwellings? Will this be enforced in amd2?

Smoke detectors are a safety service so require SPDs see BS 7671 Regulation 443.4 (i). The CRL cannot negate this, it a "shall". See DPC requirement.

More discussion on who is the Responsible Person - causing a lot of issues on my job re who that person is.

The owner of the building, the person in control of the premise or the employer. The RP is a person by default, and generally not appointed. Please refer to the RRO 2005, which is free to download from the government website.

In addition to the qualifications what else do the panel think can demonstrate competence?

If you refer to the RRO 2005 Article 18 Safety assistance - (5) A person is to be regarded as competent for the purposes of this article where he has sufficient training and experience or knowledge and other qualities to enable him properly to assist in undertaking the preventive and protective measures. Qualifications alone do not make someone competent. Demonstrating competence and ongoing commitment to keeping competence up to date can be achieved through Professional Registration. See details on the IET's Electrician EngTech award.

For emergency lighting how often should the responsible person ask for lux level checks after initial installation? only after any changes to layout or equipment?

Following the initial design and handover, the emergency lighting system should be periodically inspected and tested in-line with BS 5266-1 and BS EN 50172. Clause 6.2. of BS EN 50172 states, on completion of a yearly inspection and test schedule as required in the periodic inspection, a test certificate should be supplied to the person responsible for the premises. If the competent person undertaking the inspection and testing highlights any concerns or deviations, then re-validation of the system should be undertaken (i.e. verification of existing system). This is to ensure the system design is still valid, as certain aspects of the building may have changed. The fire risk assessment should be continuously updated to reflect any changes in risk to the premises and should be repeated on a regular basis, typically every 12 months. When undertaking a modification/alteration to an existing system, or a periodic or verification report, if the original design is not available this needs to be recorded as a deviation. Annex D(informative) of BS 5266-1 explains the procedure for measuring illuminance of emergency lighting, which highlights that measurement can be very difficult and needs to be carried out with good instrumentation and great care. Obtaining authenticated photometric data and spacing tables is encouraged in these instances, as it would provide accurate values, as these take into account worst case data.(eg no reflectance).

Does a domestic sprinkler system in residential building require a secondary supply? Can this be a second supply from the same switchboard via an ATS?

It would depend on the fire strategy for the building derived from the Fire Risk Assessment. But usually no, a second source of supply is needed.

Do we need emergency lighting outdoors? Say to exit from a 20 m high tank?

It would depend on the fire strategy for the building and the escape plan.

Has the RR (Office of Rail Regulation) been omitted as they have emergency lighting requirements for stations, particularly sub-surface where eg a full discharge test is required annually AND the station cannot be reopened until a defined duration recharge has occurred?

Advice should be sought from the Rail Regulator. We would say any building cannot be occupied with a discharged EL system as there would be no escape lighting until the batteries are charged.

When should integral illuminated emergency signage be installed and which standard defines where non integral illuminated signage is acceptable?

The use of internally illuminated directional signs are preferred, even though externally illuminated signs are permitted. This is due to the internally illuminated sign being more prominent and why the viewing distances half when externally lit signs are used. When we use externally lit signs, a minimum of 100 lx should be provided during normal lighting and 5 lx during an emergency. (Refer to BS 5499-4 Clause 5.2, 5.3). This is particularly important to identify emergency escape routes that would not normally be used, with people familiar with the location. It also worth confirming requirements highlighted in the fire risk assessment, fire strategy, local authority requirements and any requirements that the building may have in place. (typically buildings open for entertainment or places of education may stipulate internally illuminated signs).

Are documented escape routes essential?

Yes. The escape plan should be derived from the Fire Risk Assessment.

For sprinkler pumps, are cables and fuses sized for one pump at locked rotor current and the full start current of the second? Is this originally from a middle eastern standard or NFPA code?

This will depend on the fire pump control panel. A selectivity study should prove that downstream fuses will operate 1st leaving the second pump to change over to a healthy supply.

Does the panel have an opinion on the use of Fire Suppression systems in electrical control rooms and best practice?

Any requirement would be defined in the fire strategy for the building derived from a fire risk assessment.

When at the hand over of the EML system we have experienced Clients who do not know who the RP is, if the design meets to need for use. How as a contractor do we protect ourselves from people who have know real interest in what they are there for?

The default Responsible Person under the RRO 2005 (Article 1 Meaning of “responsible person” (3)) would be the owner of the building, the employer or the person in control of the premises. Covering letter on file kept by contractor describing the handover just in case!

We seem to have a lot of issues in obtaining fire strategy reports prior to designing - expectation is that we as Electrical Engineers should decide system categories etc. Is this a common issue? Who is responsible for providing?

A common problem. You cannot do the design without a fire strategy. The owner of the building or project or person appointed by them, a Fire Engineer.

In a fire alarm situation, why do most if not all lifts go to the ground floor. If a fire is on the ground floor why is the lift not directed to another floor for safe exit?

How the lift reacts to a fire alarm should be defined in the fire strategy for the building. It would be reckless for the lift to home to a floor where there is a fire.

It's interesting the mention on compliance in terms of local authorities. Budgets sometimes take precedence & we are all aware finance should not be the driver for life safety systems but it's a battle sometimes.

Yes unfortunately that is the case. The decision maker should be made aware of the possible consequences of his/her decision and a record kept for possible future enforcement action or investigation purposes.

In a small theatre venue staffed entirely by volunteers how would you suggest appointing a responsible person, and what training would be recommended? Or would this more likely fall on the resident qualified electrician to take on the role?

Training courses are available from a number of training providers. The selected person should be trained to discharge their duties.

If you have a variety of products over multiple sites how best can you achieve compliance especially when older installations will have potential deviations to current standards. Can we still cert these (a snapshot in time) highlighting for future programs of work?

For fixed wiring compare the installation to the current edition of BS 7671 and record any non-compliances. For EL there is a question on the periodic report "is the design still valid".