ELECTRICAL SYSTEMS


will be required for operating theatres, intensive care rooms, MRI suites, recovery rooms, and therapy rooms, where isolated power is needed. Consideration for MIPS should include support, and compliance guidelines such as the requirements of UK HTM 06-01, as well as the integration with other UPS and generator systems installed in hospitals and other healthcare facilities.


What about batteries? When considering the batteries required, you will need to carefully rate the system, as this will affect size, weight, operating costs, regulations, and end of life. Also, depending on what power is needed, there may be other systems in place that need to be considered and included for back-up. Battery failure is the most common cause of emergency power failures, so maintenance is essential. There are three key things that can affect a battery’s capacity. These are temperature control – too hot will reduce life, too cold will reduce performance, overcharging – which causes gassing, drying out, and potentially, thermal runaway, and undercharging – which causes sulphation and a loss of capacity. HTM 06-01 also makes the recommendation for 10-year batteries, and includes guidance on battery terminals and fire-retardant batteries. There are also two key things that will


help extend a battery’s end of life and reliability – monitoring, which allows identification and the replacement of weak batteries, and active management systems that balance charging across batteries, preventing under/overcharging, and extending service life by up to 30%.


Emergency lighting Healthcare environments are complex, and require emergency lighting that operates reliably when called upon, and provides sufficient illumination along all escape routes and to all other points where it is required. This can make the difference between safe management of a power disturbance, and panic, injury, or possibly even death. Emergency lighting is an essential part of any building services installation, and subject to extensive British and European legislation. The Department of Health’s HTM 06-01 document advises on healthcare electrical services, including emergency lighting. The guidance states that emergency lighting – escape, safety, and standby – should be designed to BS 5266-1 and BS EN 1838. Fully compliant equipment is required throughout healthcare buildings such as hospitals and clinics, covering escape routes to the ultimate place of safety, appropriate exit signage, and open area lighting – for example in science laboratories, retail units, and commercial catering. Escape and safety lighting can be


powered by central battery inverter units. However, operating theatres, which are


The high-performance Power Wave EL100XA static inverter with single-phase input and output, which Kohler UK says ‘provides emergency battery power using state-of- the-art technology’. The EL100XA series is available as a wall-mounted or standalone unit from 500 VA to 3000 VA, and is designed to fully comply with EN 50171.


risk grade A – the most critical – must have independent battery inverters for the operating theatre lamp(s) and satellite lamps. Emergency lighting, by definition, depends on a continuously charged battery back-up power source. The lighting set-up should be able to detect a mains power failure and switch to battery back-up automatically and immediately. The battery power source must be well- designed, well maintained, always fully charged and ready for use, and compliant to EN 50171 central system standard.


System set-up Carry out a risk assessment regularly. As part of your system set-up, audit the current and future power requirements so that you can estimate the load that you need to support with power – and, more critically, keep running should the mains power fail. Calculate how quickly the mains power will take to come back on, and review what needs back-up support until this happens. Is there equipment such as critical life care that needs its own power and back-up supply? One way to look at this is to review the types of power required: 1. What are the medical requirements? 2. What are the lighting needs? 3. What mechanical equipment is already in place?


4. What emergency equipment is needed? 5. What requires isolating?


Once you have done this, you can look


to see if the power requirement needs its own source, or whether it can be fed from the mains power. You will also need to check whether it requires single or dual source power to ensure that back-up will be comprehensive and meet compliance guidelines.


Dual supplies for extra resilience For extra resilience, dual supplies are provided at the final circuits, and each source may have a central UPS system configured for N+N. Generally, a central UPS will have a single source. A UPS at the final circuits may require dual sources. Having said this, no medical or healthcare facility is the same as another, so ensure that the risk assessment and equipment audits happen on a regular basis, are noted down, and communicated with the team, accordingly. Speak to your UPS supplier regularly, as it will be able to assist with the system design and changing requirements. A key consideration for the system


installation and maintenance is how the UPS will be monitored. Will there be a:


n monthly visual check? n daily visual check? n remote alarm signal? n BMS connection? n network and email connection? n remote monitoring by supplier?


Ensure that whatever plan is put in place is regularly reviewed, and – where possible – use your supplier as a critical friend to help with these audits.


February 2024 Health Estate Journal 63


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