Emergency Lighting, the clue is in the name! It’s there for when things go wrong and will save people’s lives. It’s a life-critical application.
When disaster strikes, reliable emergency lighting is crucial for safety and evacuation. Therefore, it’s vital that the correct electrical back-up solution is in place. Hence my question in the title… can you use a UPS (Uninterruptible Power Supply) or a Static Inverter/CBS (Central Battery System) to provide power to the emergency lighting system during a mains failure?
In very simplistic terms, UPS and Static Inverter systems provide backup power in case of a power outage however, their primary functions do differ. A UPS is designed to protect critical electrical equipment, nominally IT, whereas a Static Inverter is specifically designed to maintain emergency lighting for a specified duration. So, whilst technically there is synergy in their conversion technology, the application, and regulatory requirements, dictate that they are very different animals.
Therefore, the simple answer is, no you cannot use a UPS and, yes you must use a Statice Inverter/CBS. But why? Let us explain:
Understanding The Basics
Firstly, although the acronym CBS is often used to cover all emergency lighting systems, there are some variations, for example a CBS is typically AC Input /DC Output and SI generally stands for Static Inverter which is typically an AC Input/AC Output (single or three phase)
In brief, Emergency lighting is a range of backup lights that will operate fully automatically in the event of an emergency situation, nominally electrical power failure. It provides sufficient illumination to enable all occupants of a building to evacuate the premises safely during a blackout.
Regular testing and maintenance are crucial for ensuring your emergency lighting system works correctly and as intended.
The Importance Of Emergency Lighting Standards
Emergency lighting is regulated by standards like the Regulatory Reform (Fire Safety) Order 2005the base guidance document BS5266, BS50172 which specifies the minimum provision and testing regimes of emergency lighting systems, and BS EN 50171 which specifies the central power systems.
The Regulatory Reform (Fire Safety) Order 2005 (FSO) is the primary legislation governing fire safety in non-domestic properties in the UK. It requires people such as building owners or employers to install suitable emergency lighting based on a building’s risk assessment findings and building regulations.
You can’t just supply a “box and batteries”.
And, importantly, the law does place some responsibilities on the supplier/manufacturer.
Adhering to these standards is not just a case of supplying and installing the correct system, but also incorporates the responsibility of the manufacturer to ensure that the emergency lighting installation meets the required standard.
For example, the size and type of fuse(s) or protective devices installed in the distribution system shall be specified by the manufacturer, and the central inverter shall be capable of tripping any associated protective device installed in final or distribution circuits, without shutting down the device or rupturing its output protective device. Failure in one of multiple output circuits does not lead to a failure of any of the other output circuits.
Staying Up To Date With Regulations:
Delving briefly into BS50171, by the way, the latest amendment BS50171-2021 comes into law at the end of 2024; there are many specific technical aspects that are required in a CBS that a “traditional” UPS does not incorporate.
From the simple rating plate on the EL unit clearly stating load and battery autonomy/battery type etc, to internal wiring that must be permanently marked, subcircuit and phase failure monitoring, recharge characteristics i.e. 80% in 12 hours, through to a battery charger with short-circuit that will not cause damage to the unit itself …and many more!!
And, of course, those batteries have to be sized correctly at End of Life, (EOL), which in itself is a topic for debate, and a pet subject of mine, on how to calculate autonomies correctly!
Note Para 6.6.11 of EN50171 does state:– Where a UPS system is used to feed the essential safety systems, it shall comply with EN 62040-1 (a UPS design standard) AND the additional requirements of this document.
So, while a UPS can be adapted for emergency lighting, a Static Inverter is inherently designed to meet these standards. Now we know that you are required to install a CBS system for an Emergency Lighting application.
And it’s not just a case of buying and installing an emergency lighting system, it must be maintained correctly.
Maintenance, Testing And Commissioning Of Emergency Lighting:
Under the above-mentioned regulatory reform, Para 17 Maintenance – the responsible person must ensure that there is a suitable system of maintenance in place and that systems are maintained in an efficient state, in efficient working order, and in good repair.
Regular testing and maintenance are crucial for ensuring your emergency lighting system works correctly and as intended. Government guidelines stipulate that all emergency escape lighting systems should be tested regularly.
Traditionally, manual testing is carried out however, emergency lighting devices are now available with self-test facilities.
A typical test uses a key-operated switch, a ‘secret key’ that lets you test the emergency lights whilst preventing the operation of the test switch by non-authorised personnel. It is often found near the main fuse board or relevant light switches.
In addition, it is advised to keep a record of all tests carried out and any relevant findings in the fire safety logbook. Even though this is not compulsory by law, it is useful for demonstrating compliance with fire safety legislation.
Testing Would Usually Include The Following:
- If it’s a centrally powered system with extra lights, conduct daily visual checks on the central controls.
- A monthly function test should be carried out by operating the test facility long enough to ensure that each emergency lamp illuminates and is working.
- An annual full discharge test to ensure that the lamps stay on for the full discharge period (usually 3 hours) and that the batteries are recharging properly.
Caution needs to be taken following a full discharge test. This is because batteries typically take 24 hours to re-charge. Hence, the premises should not be reoccupied until the emergency lighting system is fully operational unless alternative arrangements have been made.
Not All Emergency Lighting Systems Require The Same Type Of Solution.
There are four main types of emergency lighting:-
- Escape route lighting: the means of escape out of the premises is effectively identified, sufficiently illuminated, and can be safely used by the occupants of the building. This helps reduce panic and identify evacuation routes and obstacles in emergency situations.
- Open area lighting: sometimes referred to as anti-panic lighting and applies to floor areas larger than 60m².
- High-risk task area lighting: provides higher levels of illumination to allow potentially dangerous processes to be shut down or stopped prior to evacuation, for example turning off major machinery equipment.
- Stay put/emergency safety lighting: Occupants will be allowed to stay in the premises until there is less than 1-hour duration left in the emergency lighting. The system then allows them to be directed or escorted to a low-risk location. It must be clear how long occupants can stay and how the end of the ‘stay put’ period will be indicated.
In Conclusion:
Reverting to my original question…..do I, or can you, use a UPS (Uninterruptible Power Supply) or a CBS (Central Battery System) to provide power to the emergency lighting system during a mains failure?
Hopefully, we have clarified the answer to that question, and you will not be a penitent man and use a UPS system where an emergency lighting system should be installed.
ALL occupied buildings, whether new or old, require emergency lighting. With today’s highly populated office blocks, Emergency lighting is a vital aspect of building safety to ensure everyone can evacuate safely in the event of an emergency situation.
Supplying, installing, and maintaining an Emergency Lighting system has statutory legal obligations on the designers, manufacturers, installers and those responsible for maintaining them.
Emergency lighting is essential for protecting occupants during emergencies, making it of utmost importance for building owners. The consequences of not complying with the law can incur costly fines, closure of businesses, or even prison sentences.
Fortunately, BPC Energy offers a range of high-quality Static Inverter systems that meet the highest standards for emergency lighting, and specific, bespoke, requirements are designed in-house and manufactured in our own workshop facilities. Our PowerPro EL range of Static Inverter Systems are designed specifically for emergency lighting applications.
Our expertise and commitment to quality make us your trusted partner in creating and maintaining safe environments. Investing in a reliable emergency lighting system is crucial for protecting lives and property.
By understanding the differences between UPS and Static Inverters, you can make informed decisions to protect your building and its occupants.
Contact BPC Energy today to learn more about our Emergency Lighting solutions.
Thank you for reading! Head to our website to learn more about Emergency Lighting backup systems and be sure to follow us on LinkedIn, X, Instagram, and Facebook for more power protection and related backup solutions.
Author: Mike Elms – BPC Energy’s Sales & Marketing Director