This is more complicated than you can imagine as we constantly deviate from the original design intent through a lack of knowledge of how the scheme works, or by value engineering without considering the impact of product placement or photometry.
Often the scheme created by the engineer will be based on a design and build project where the use of the space is not yet decided so a blanket scheme is created that doesn’t factor in meeting rooms, corridors etc
Based on an open plan approach these schemes are compliant but once partitions are installed cellular offices created then the scheme needs to be re-engineered to meet the requirements of the final installation.
Often, there is no re-evaluation of the scheme and it is left to the installer to make decisions on where to place additional emergency luminaires. Competent engineers will understand they need to add additional luminaires, but this may be on a more Ad hoc basis than through design.
Ultimately someone needs to accept responsibility for the design of the emergency lighting installation, and this is where it becomes somewhat complicated.
The M&E company or Lighting Designer who created the original scheme may no longer be involved with the project so the contractor undertaking the client fit out will have to take on the responsibility for amending the scheme to ensure compliance. To be fair many good electrical contractors do an admiral job in using their experience to add emergency lighting and will often err on the side of caution and add more than is necessary.
Where they do fail is, when they are working on a price alone as performance criteria may not be first on their list of requirements. Also, if there is any form or automatic testing, the selection of an appropriate invertor maybe overlooked.
So, do we have a coherent scheme that stands up under scrutiny?
Well that is the question and often this may not be the case as the original scheme is no longer valid and the modified scheme is not designed so how do we achieve compliance?
You could use a qualified lighting designer, which is the route that I would promote or the services of a good lighting company whose designers are capable of delivering a compliant scheme. The Luminaire manufacturer will certainly take design responsibility for their products, but I can’t imagine them accepting any responsibility for the incumbent emergency products. The lighting designer on the other hand is not affiliated to a single manufacturer so will provide independent advice.
Remember Emergency Lighting is a life safety system and you as the Building owner or occupier of that space if rented are responsible for the safety of your staff and any visitors.
Ultimately you pay your money and takes your choice!
Maintenance is an area where emergency lighting doesn’t have a great track record and this in part is due to poor testing and replacing batteries with non-OEM approved cells.
Manual testing where you use a key switch to turn off the mains and force a test is a dated method of testing that provides no record of when the test was conducted and for how long. It is open to abuse and consequently can in certain instances mean that replacement batteries that are not capable of delivering their full rated discharge.
Self-test systems are a step in the right direction and do give a visual indication that a test has been taken with both function and duration tests on a randomised algorithm based on a 28-day cycle. The downside to these systems is that the testing is random so could occur in the middle of the day and you still need someone to walk the building to ensure you have no red indicators. Also, if you don’t report the error then no action will be taken to correct the fault.
Automatic test systems are in my opinion the way to go as you can select the test time, customise the test periods and validate the tests in accordance with standards such as BS EN 62034:2012 Automatic test systems for battery powered emergency escape lighting. Central battery systems can also be tested and validated so solutions are available for a wide range of applications.
Battery replacement is a concern as batteries are matched to the Original Equipment Manufacturers (OEM) invertor and control circuit. The CE mark is applied to the system which is the driver and battery and often the light source if a standalone emergency luminaire. The characteristics of the battery chemistry and charge regime are optimised for that system as well as the thermal performance and lumen output.
Therefore, when undertaking any maintenance, you should replace with OEM batteries or an approved battery. If you decide to use another battery, then any CE mark from the original equipment manufacturer is no longer valid and the company replacing the battery should submit the product for testing and re-label accordingly.
So again, measuring compliance is a tricky one because if you have replaced a battery within an emergency luminaire and sourced this based on price or convenience rather than going back to the original manufacturer you potentially have a non-compliant luminaire.
The reality is that for years contractors have gone to their local wholesaler and bought a battery off the shelf and installed it, and in the most part have had no issues and this is partly true.
Remember manual testing is open to abuse and a basic power on will prove that the battery is functioning, and the replacement battery will be signed off, the rise of automatic test systems however provides no wiggle room and a non-compliance will be highlighted immediately.
Automatic testing is highlighting bad practise and its essential that batteries are matched to the original manufacturers’ product and that when a suitable replacement cannot be sourced that testing is undertaken to validate the replacement.
Good design will optimise your emergency lighting whilst ensuring compliance, no matter what stage of the construction process.
Automatic testing will validate testing and provide a history of both testing and maintenance.
Finally, always replace batteries with OEM product to maintain compliance and safety.
if you would like any further information on emergency lighting please don’t hesitate to drop me a line.
Stewart Langdown FSLL