At KUP we spend much of our time working with data centre operations and other ICT equipment power protection applications. However, we’re also involved in many other areas where uninterruptible power supplies are just as critical – and one of these relates to lifts and smoke extraction within buildings. Our enquiries for this application have increased significantly over the last couple of years, ever since a change in UK legislation which means that all lifts intended for evacuation use must now have an emergency backup power supply, in order to meet the BS 9999 Annex G (Fire regulations) standard.
These lifts are provided to give priority to the evacuation of disabled persons when stairs are not an option. They allow the building management to evacuate these individuals, as they are not permitted to evacuate themselves. In the event of a power outage a secondary, independent emergency backup power supply is required. In many cases, we have seen that providing a secondary power supply into the building simply isn’t possible, so an onsite UPS power supply, backup generator or combination of both must be used instead.
UPS power systems should be protected from fire for 30 minutes – the same period as that given to the refuge area. The cables for the backup uninterruptible power supply should be separated from those for the primary supply and should be routed through a low-risk fire area. The lift in question must be provided with communication from the main floor to the car and to the machinery room.
These situations, which typically call for a UPS capacity of 20 – 50kVA, can be handled by products such as the KOHLER PW 5000/TP. This is a standalone three-phase UPS system available in seven power ratings from 10 to 50kVA, and in different cabinet sizes to allow UPS battery capacity to be matched to the application’s requirements. The KOHLER PW 5000/TP is a true online, dual-conversion VFI (Voltage frequency independent) type of UPS power supply that offers exceptional reliability and high power protection and availability for this application’s critical demands.
The KOHLER PW 5000/TP uninterruptible power supply also offers cost and space-saving benefits that appeal to building managers who must accommodate this extra support hardware. Energy costs are minimised through innovative transformer design and Energy Saving Inverter Switching (ESIS) technology, which achieve up to 95.5% energy efficiency. Running costs are also reduced by temperature controlled UPS battery chargers that extend lifetime performance. The compact UPS power supplies design minimises floor space with a footprint of 0.4 m2 at 50kVA, with a power density of 100 kW/m2.
Specifiers and installers of UPS systems intended to support lifts should be aware that some lifts have regenerative braking, which generates a potentially damaging back–EMF onto the DC Bus within the uninterruptible power supplies. However, we can prevent problems by supplying UPS power systems within additional circuitry that quenches this back-EMF energy.
If a power outage of longer than 3-4 hours is a significant risk, the UPS power supply can be backed by a KOHLER PW J Series standby generator. This is available in several ratings from 22kVA for three-phase applications. Each model is built with a high-performance John Deere engine for reduced noise pollution and improved fuel efficiency and is available as an ‘open’ backup generator or within an acoustic enclosure to further minimise noise emissions. Run time varies from 9 to 60 hours depending on the model and fuel tank size.
Whether an uninterruptible power supply alone is sufficient, or the application calls for a backup generator as an alternative secondary power supply, we are well-positioned to help building managers provide cost and space-effective secondary UPS solutions that comply with the new legislative requirements.