Speaking in a topical session at the IHEEM Wales Regional Conference in Cardiff on 11 May (see also HEJ – August 2023), Anthony Pitcher, Senior Fire Safety Adviser, NHS Wales Shared Services Partnership – Specialist Estates Services (NWSSP – SES), discussed some of the key fire safety challenges when seeking to decarbonise healthcare buildings – for instance those arising from large-scale use of timber as a ‘standout feature’ in building structures, and around the combustion risks from electrical vehicle charging points.
Anthony Pitcher began his presentation – titled, ‘Principles being adopted and challenges to be considered for fire safety and the decarbonisation agenda’ – by admitting that the decarbonisation agenda had ‘caused much recent head-scratching’ among fire safety professionals; currently, there were ‘more questions than answers’.
Starting by focusing on embodied carbon, he showed a slide of the ‘Construction Materials Pyramid for Embodied Carbon’ – ‘an interactive online tool for comparing the global warming potential of various construction materials’ (Figure 1). He said: “You can see that the materials towards the top of the pyramid (such as steel, concrete, and bricks) are very good from a fire safety perspective, but pretty damning from a global warming one, whereas those at the bottom (such as straw, and wood-based products) are great from a carbon perspective, but all pose a fire safety challenge; they burn nicely.
He next showed a CGI of the atrium (Figure 2) at the new Velindre Cancer Centre in South Wales – which the architects, White Arkitekter, and the project sponsors, Kajima, / Sacyr / ABDN and ‘projectco’, ACORN, say is ‘set to become the UK’s greenest hospital’.
“You can see that the atrium is a pretty impressive pretty space, with the primary structural materials being mass timber CLT and glulam beams,” Anthony Pitcher explained.
Char insulates the inner core
While impressed with the aesthetics of the predominantly timber-structured atrium, the speaker said that, ‘from a fire safety perspective, we all know that timber burns, so we have a bit of an issue there.” He told delegates: “In fact timber is a pretty unique material – when it burns, it effectively protects itself, forming a char which insulates the core.” Char factors were, he explained, predictable, depending on the type of wood, the species, and the moisture content. “Typically,” he explained, “we’ll be looking at char factors of around 1-1.5 in / hour, so wood can really be considered a unique material.”
Looking at the various relevant design codes, Anthony Pitcher said that while these assumed uniform char factors with ‘normal timber’, mass timber didn’t necessarily burn the same way, and can be subject to a process of delamination. He explained: “What happens is that exposed wood burns, chars, and the char can then fall off, exposing more clean wood behind. You thus get into a process of ‘cyclic burning’.”
Key factors to impact on cyclic burning included the number of layers and the composition of the wood, as well as the types of fire-rated adhesive. The speaker added: “There is another approach you can use to protect the timber – encapsulation, where you encapsulate the mass timber in plasterboard.” He continued: “I’m sure you’ll all agree that the atrium at Velindre wouldn’t look half as impressive if it was just a boarded plasterboard structure, concealing the natural beauty of the wood – so that form of protection kind of defeats the aesthetic objective.”
One of the key considerations with timber – and particularly mass timber – Anthony Pitcher said – is that it is ‘a bespoke product’. He elaborated: “It is unique to the individual supplier, so we can’t mix and match. This presents some challenges in fire safety testing which – post-Grenfell – have become even more stringent.”
Joints and penetrations
Turning to some of the other fire safety ‘implications’ around mass timber, Anthony Pitcher said: “We must really focus on the detail in the joints and penetrations. Weak joints can potentially risk the integrity of the compartmentation. When we look at the various materials and tests, there’s a scarcity of tested details for penetration seals, particularly for CLT.” Acknowledging that the industry was ‘improving in this area’, he cautioned: “I’ve yet, however, to see a tested detail of a fire damper being installed directly into a CLT form of construction.”
Turning to ‘building geometry’, the speaker said: “Here we’re looking at large spans and deep beams. We recently reviewed a scheme which utilised CLT and glulam beams, with 24 metre timber spans.” The scale and the size of the timber had been ‘incredible’. He explained: “The columns were about 2.5 feet square, and the beams six feet deep.”
Such construction and timber components posed some fire safety issues. Anthony Pitcher elaborated: “With a relatively flat ceiling, it’s easy to work out the detector spacing and the sprinkler protection, but a large space – broken up with extremely deep downstand beams – has implications in terms of elements such as a need for more automatic fire detectors (AFDs), and the sprinkler protection will be steered by that too.” Anthony Pitcher said another consideration was that deep beams can restrict ceiling voids. He explained: “We all know how congested hospital ceiling voids are – for elements such as services and maintenance etc.”
Impact of future modifications
The fire safety specialist said one element that the sector perhaps paid insufficient attention to was potential future building modifications. He said: “The NHS is continuously evolving, and if we are using CLT mass timber, we need to determine whether this imposes restrictions on future flexibility.”
On what he dubbed a ‘positive note’, he added: “If you’re using materials of limited combustibility for your structural elements, then the building will be sprinkler protected – from a fire safety perspective this is a huge step in the right direction. I am very ‘pro sprinklers’, and we have achieved extensive progress in Welsh healthcare facilities with sprinkler protection, which will hopefully continue.”
The NHS Wales speaker’s next focus was guidance. He explained that bodies such as the Structural Timber Association, and RISE (The Research Institute of Sweden), had produced ‘masses of guidance’ on this topic (Figure 3). “However,” he added, “they recognise that it is an extremely specialist field. As several previous speakers said earlier today, there is also a massive skills shortage in this particular area.” There was, however, ‘a lot of ongoing research, with a continuously evolving database and evidence base’.
The speaker’s view was that the NHS isn’t yet ready for mass timber construction. He added: “Perhaps I should qualify that. The images we saw of Velindre show an atrium – so there is no direct patient care there, while, importantly, the building has full sprinkler protection against fire. Also, on the scheme there are other parts of the building – on the upper levels – which are purely administrative, with no patient access. Again, mass timber has its place, but I don’t think the NHS is ready for mass timber in inpatient facilities. That’s my view, but – as I said – there’s a lot of research ongoing, so maybe things will change in the future.”
Here, Anthony Pitcher said he wanted to discuss ‘electrification’. He said: “Why is this such a concern to us in the NHS? Well – statistically, and consistently, over the past 10 years, the biggest cause of NHS fires has been some form of electrical failure (Figure 4). We are putting everincreasing demand on the electrical infrastructure, and as several speakers this morning recognised, the estate is tired – and so is the electrical infrastructure. We must therefore be very careful about what additional load we add.”
Operational carbon
Turning to the operational carbon associated with various forms of electrification, and Anthony Pitcher said one of the most significant changes is the adoption of photovoltaic plant. He said: “Some 99% of all the business cases that come across our desk for scrutiny today include PV installations. There’s a massive growth in PV, and rightly so, given the decarbonisation agenda.” Looking at some of the key PV system components, the speaker explained: “The DC cabling is extremely dangerous, and thus the Fire Service needs to isolate it; any delay in doing so could hold up firefighting activities, which could have significant consequences for the outcome of the fire.”
Showing a slide of the key components of a PV system, he highlighted the PV panels on the roof, a DC cable shown in red, and its feed into an inverter. The inverter then fed out AC cable connected to the electrical infrastructure.
It was vital, he stressed, for the DC cabling to be isolated. “So,” he asked, where do we isolate? Well, ideally,” he responded, “you should be isolating at source. However,” he explained, “this is one of the problems we have.” Now,” he added, “the image on the right (Figure 5) on a slide titled ‘PV fire-fighting risk’ is an isolator.” On it – in small text – is the message: ‘Solar PV Firefighter Switch, Please note: DC voltage will be reduced to a safe level’. The speaker said: “I’d question that. Without sufficient information, is that just to isolate the AC supply to the inverter to turn the inverter off? If so, the red cabling coming down from the PV panel to the inverter has potentially still got significantly high voltages running through it. We need clearer information on that.”
Showing another slide (Figure 6), he said: “This is a pair of inverters, with the red isolators being the AC ones, and the grey ones the DC string isolators.” This equipment was located in a hospital ward pantry, ‘not the safest place to install such kit’. He said: “These are some of the challenges we are facing.”
As to the fire safety risks from PV arrays and associated equipment, Anthony Pitcher said that ‘when one thinks of the millions of panels and systems installed across both the NHS estate and many installations in other sectors, they don’t catch fire every day’. The BRE and the IEC had ‘conducted a fair bit of research’ on this, which was now ‘slightly dated’. He said: “They identified that the most probable or common causes with PVrelated fires were poor installation and component failure, and instances where there was water ingress, or inappropriate AC / DC isolators etc.”
A continuous arc
He went on to explain that DC current gives a continuous arc, with a higher associated ignition risk. He said: “Look at the burnt isolator image on the right of this slide (Figure 7), and some of you will recognise it. We had a PV-related fire incident last Friday. Stuart Douglas (the Director, NHS Wales SSP – Specialist Estates Services) called me one night recently and told me we had a PV-related fire in an isolator – in fact an AC isolator on a DC circuit. They’re not compatible – as you can see from the photo. So, again, some of the challenges to consider.
Moving to look specifically at PV installations, Anthony Pitcher said there were many modes and methods of installation. However, he told delegates, ‘from experience PV installations are generally driven by energy consumption, without all that much thought about the fire safety consequences’.
Taking as an example a combustible EPS roof with a bitumen felt covering, he asked: “Should we really be putting PV panels on top of that?” Another question might be: ‘If we have fire compartment walls abutting the underside of a roof, should we have PV panels spanning across the top?’
While these were ‘questions that needed to be asked’, Anthony Pitcher said that ‘if it wasn’t in the guidance, it wouldn’t be done’ – adding that there was currently a lack of guidance around such subject matter. He said: “We also need to consider the inverter types and locations. Is it appropriate to have inverters and isolation facilities buried deep within the building? Or, should things like the isolation switches be located at the Firemens’ entrance?”
Here he turned to the key fire safety information that, say, an NHS Trust, should be able to offer the Fire Service. He said: “The Fire Service should be able to turn up on site, confident that the system has been isolated. We’re not just talking about a fire with the PV side of it, but a fire in the building. If there’s PV on the building, it will have an influence on what the Fire Service personnel do. If they believe there’s cabling going through the area that they’re working in, it could have implications.”
Schematic plans
“So,” he told delegates, “we should have schematic plans, illustrating – particularly – where the DC cabling is, together with documentation, risk assessments, and fire manuals. These should all be there, but are often overlooked. The last point to draw attention to on this slide,” he added, “is the maintenance regimes. Most PVs are specialist pieces of kit, and you will probably have service agents looking at the PV inverters etc, but how many PV maintenance regimes are checking things like mechanical fixing of the panels, or debris build-up?” Debris build-up on the panels was ‘extremely attractive to nesting birds and rodents’, including squirrels – he had personal experience of what the latter could do.
He told delegates: “Returning to the fixings, and in the incident involving the burned out isolator I showed you earlier, as part of the system there were three PV panels on the roof that had been dislodged during storms. Whether that was a contributing factor to the ‘short’ and the ignition source the Fire Service identified we don’t yet know – the investigation is still ongoing – but it does highlight the fact that PV panels on top of roofs are pretty exposed, and we must ensure sure they are adequately maintained and serviced.”
Bristol Museum fire
At this point Anthony Pitcher showed an image of a fire at Bristol Museum during 2022, thought to have been caused by birds nesting, again illustrating that, ‘just occasionally, PV systems are a risk’. As regards official guidance on the subject, he explained that among the key documents would be RC 62, Recommendations for fire safety with PV panel installations, and the IET Code of Practice, Grid-connected Solar Photovoltaic Systems (Figure 8)
He said: “There are lots of other guides, but due to the number of queries we are getting around PV systems at Specialist Estates Services, we are looking at issuing guidance in the coming weeks. This will cover best practice, and promote and address some of the points we’ve raised during this presentation.”
Anthony Pitcher told the audience he would next address lithium batteries. He said: “Certainly we are seeing more and more PV installation, some of which includes localised lithium battery storage, or BESS systems. Of course lithium batteries are now such a common part of everyday life, which I think leads to some complacency. We are blissfully ignorant of the risks surrounding them – and consequently see some bad practice. How many of us are guilty of leaving our mobile phones on charge overnight, or using our laptops on the bed or resting on the floor and the carpet when we’re charging?”
The speaker went on to explain that NHS Wales SSP-SES had had reports of staff taking extension leads out of windows in staff residences to charge their electric vehicles, parked up against the building. He added: “We also know of staff taking the batteries off their ‘e-bikes’, and charging them under their desks.”
Anthony Pitcher said all such instances posed ‘a very real risk’. He said: “At the lower end of the scale, the mobile phones and laptops have nothing to do with the decarbonisation agenda, but it highlights what we do with these batteries, and the potential risks. When we look at increasing energy density, unfortunately the fire risk is elevated as well.” He next played a short video featuring several lithium battery-related fire incidents, with increasing energy density – with the devices involved ranging from mobile phone and e-bikes, to EVs and electric buses, highlighting the sudden explosive and volatile nature of failing lithium batteries.
Anthony Pitcher said that while these weren’t necessarily daily occurrences, ‘we should nevertheless be prepared for them’. He next explained that the key failure modes with lithium batteries are short circuit, overcharging, or mechanical damage. He said: “As you could see in the slides, if such a battery starts to deteriorate, it self-heats, with an exothermic reaction, and ‘thermal runaway’ can occur, leading to ‘gassing off’, and then potential ignition. Of course it’s not just the flames and heat release from such incidents that are dangerous; the associated vapours are highly toxic.
Extinguishers
The speaker next asked: ‘So, what do we do in terms of extinguishers?’ Answering his own question, he explained: “There are a number of solutions available; Lith Ex is one particular product – a vermiculitebased solution, which is very effective for putting out lithium fires. Should we,” he asked, “be providing these extinguishers across our estate, and encouraging staff to tackle lithium battery-generated fires? From my perspective, absolutely not.
You’ve seen how quickly things can get out of hand; if you have such an incident, turn your back on it and get out. These are some of the questions; it’s an ongoing debate, and we don’t yet have all the answers.”
Anthony Pitcher said he would now turn to UPS and battery energy storage systems (BESS). He said: “Here the focus should be looking at what the sector dubs ‘Proportionate Precautions’.” He asked delegates: “But what does that look like? Should we have a sliding scale stipulating that – for example – a 20 kilowatt hour (kWh) UPS needs half-hour protection, a 50 kilowatt unit one hour’s protection, and a 100 kilowatt UPS an hour’s protection plus suppression? We don’t currently have the answers, but these are some of the things requiring discussion.”
He continued: “We can’t do much about UPS system location because they generally need to be pretty close to the equipment they’re protecting, because of voltage drop etc. However, we can certainly look at enclosure protection. Also, on a related note – going back to energy storage systems – should we even be contemplating putting BESS systems inside our buildings? I’d suggest installing these in an outside car park or service yard. Another key consideration is firefighting access, where quick access is essential
While there is plenty of guidance already available on lithium batteries, none of it is NHS-specific, the speaker emphasised. He explained: “None of it recognises that we have patients with mobility impairments, and progressive horizontal evacuation strategies where we’re keeping people inside the building, nor the use of oxygen we have NHS-wide. So, there are clear gaps in the guidance and our knowledge base.”
Existing lithium battery guidance
Discussing the guidance that does exist, Anthony Pitcher explained that the RISCAuthority RC61 guidance is a ‘pretty good guide’, as is the Euralarm guidance on Integrated fire protection solutions for Lithium-ion batteries. He added: “Research is ongoing, and of course the whole suite of Firecode (HTM 05-02) is up for review. The implications of the decarbonisation agenda will be covered in that. However, in advance of this – because Firecode is 12-18 months away, NHS England is looking to issue some interim guidance on the risks associated with the lithium batteries – which should be available soon.”
Here, Anthony Pitcher said he would discuss the third major topic in his presentation – electric vehicles, or ‘EVs’. He said: “We all want EVs that go further, and can be charged faster, but that comes with elevated risks.” While EVs didn’t catch fire every day, when they did so, it could be ‘pretty serious’.
Looking at UK projections from the Climate Change Committee (Figure 9), the statistics showed that there are currently around 40 million cars registered on UK roads, and in the next 10 years, at least 50% of them will be EVs – ‘a massive change in in our vehicle network’. The speaker said: “Not necessarily a life safety risk, but the biggest challenge facing us with more EVs is from a firefighting perspective.” Discussing some key points set out in the firefighters’ Standard Operating Procedures for EVs, Anthony Pitcher said they recognise that EVs burn hotter and faster than standard internal combustion engines, and recommend cooling the batteries with water, ‘and a lot of it’. He said: “The ‘SOPs’ also recommend monitoring the lithium-ion batteries with thermal imaging cameras, to assess the risk of thermal runaway conditions.” The SOPs also recognised the significant risk of re-ignition. He added: “So, if you get an EV fire, it’s unlikely the firefighters will move the vehicle for a significant period.”
Water run-off
Another element to consider was water run-off, and the need to contain contaminated water. Anthony Pitcher said that if you currently asked any firefighter what their biggest challenge is, the majority would reply ‘Tackling EV fires’, ‘because they haven’t got the answers yet’.
Next, he showed slides from various European countries, where the EV firefighting strategy included submersing the car in a bath of water, and leaving it in there, ‘potentially for 24 hours’. The speaker said: “Other techniques include draping big fire blankets over the car. This will not, though, prevent thermal runaway, and may not extinguish the fire, but it will reduce the chances of car to car fire spread – a major concern as well.”
The other key priority, the speaker explained, is to cool the battery, such as by using ‘lance-like’ devices that slide under the vehicle and spray water upwards; due to the weight distribution of cars, most EVs tend have batteries on the chassis, close to the ground. He said: “However, it’s an evolving picture – and the fire service hasn’t yet determined what the best solutions are.”
Anthony Pitcher explained that the National Fire Protection Association (NFPA) website has a database of emergency response cards for all vehicles. He said: “You just tap in the car’s details, and it comes up with information on how to address a battery fire. It’s in fact not uncommon for the guides to recommend you put 30,000 litres of water on one EV. To put that in context,” he added, “if you were building a hospital in a field and didn’t have an adequate water supply, Firecode would require you to have a 45,000 litre holding tank. Potentially, however, you could be using two-thirds of that on one vehicle fire. A standard firefighting appliance will carry around 1800 litres of water. If the fire service is tackling a standard internal combustion engine fire, they will probably only use about 1000 litres, so EV fires are extremely intense, and require significantly more cooling capacity.”
EV charging
“So,” Anthony Pitcher asked, as his presentation continued, “what will you do in terms of EV charging?” He said: “There is an elevated risk during the charging process; but don’t forget that an EV that is not being charged still constitutes a fire risk. Imagine a scenario where, 10 years from now, 50% of cars on the road are EVs. We’ve already highlighted mechanical damage. A car accident occurs… and the owner takes the vehicle to a backstreet garage; they patch up the paintwork, and the car is back on the road. However, there is no telling if that damage has started a chain reaction to impact on the battery. In the future,” he added, “I think insurance right-offs with EVs will be increasingly common – since insurance companies won’t be able to guarantee that a car is safe following an accident.”
Looking at the implications of EV charging on the NHS estate, Anthony Pitcher said Estates and Facilities teams needed to consider charger location in relation to buildings. He asked: “For example, if you have a building with suspect cladding, or parking adjacent to a means of escape, should you really be putting EV charging points next to those?” The speaker also said the NHS estate was increasingly seeing solar charging for bike shelters. He said: “You have no control over the quality of these bikes, and, in addition, bike shelters are being put right next to entrances because it’s convenient for users. I would question the logic of that. We need to focus on the potential risks and impact on service delivery with these.”
Fire and rescue access and facilities
Anthony Pitcher’s next focus was fire and rescue access and facilities. He said: “Given that fire service personnel will need significant quantities of water, should we be reconsidering our hydrant positions to ensure they’re reasonably close to charging facilities? Likewise, if you have charging facilities, are your chargers manually or automatically isolated?”
He continued: “I was recently discussing an existing hospital building, which is effectively up on stilts, with parking underneath. The hospital was fitted with sprinkler protection, to an OH2 standard, but back in January the standards increased to HHP3, which stipulates significantly higher standards for water supply and duration, so we also need to consider how this impacts on our existing estate.”
Turning to discuss parking bays, RC59 recommends 1200 mm of space between cars, but the speaker said if this was implemented, the NHS would lose 40% of its parking capacity. He asked: “What about management response to EV fires; if we do get one, are we sufficiently trained on what to do? Again, it’s about knowledge and documentation.”
Electric ambulances
The speaker’s next slide showed two electric ambulances; a number of ambulance Trusts in England had already introduced such vehicles as they looked to electrify their fleets. Looking to the future, Anthony Pitcher said: “So, five years down the line, we’ve got an electric ambulance fleet, but with bed pressures, the chances are that they’re still going to be outside A&E in a queue with patients ready to offload. It’s foreseeable they’re going to ask for charging facilities there. Should we really be considering charging an ambulance outside an A&E Department? We need to be considering such things, and really focusing on the potential impact on service delivery. The other consideration,” he added, “is that a lot of these emergency vehicles, and doctors’ and district nurses’ cars, carry oxygen – another added complication not factored into any of the current guidance.”
Here Anthony Pitcher showed a slide of a burnt-out diesel ambulance that had caught fire in Swansea in April this year. He said: “This just demonstrates that emergency vehicles do catch fire – here there was an electrical cause. There was a patient in the ambulance, but luckily no one was injured. Nevertheless, it shows that these are vulnerable vehicles.”
The speaker explained that RISCAuthority RC 59, Recommendations for fire safety when charging electric vehicles, is the relevant guidance, and incorporates ‘a very useful checklist’ for EFM teams considering installing EV charging facilities. He added: “The National Fire Chiefs Council (NFCC) has major concerns about this as an issue, and is conducting a lot of research on it, and I’d anticipate guidance from them.” NHS Wales SSP was, he added, also looking at issuing its own guidance on electric vehicle charging cross NHS Wales
Looking to the future
Anthony Pitcher’s last slide focused on ‘The future’. He asked: “So, what does the future hold for us?” In response to his own question, he told delegates: “I think the industry needs to catch up and match the rate of technological development – particularly when we look at the implications of the ‘decarb’ agenda, picking up on things like the AEs and competence etc. We’ve got to increase our knowledge base, and – through events like this – share best practice. I don’t think we have enough pooling of knowledge and research. If you have a design team that has explored, and developed, a particular solution, surely we should be picking up on that and sharing it with other design teams? I know there can be competitive and contractual issues, but equally, if you have a design solution and have ruled it out for a particular reason, let’s share those reasons, so we are promoting a pool of learning and resource.”
Anthony Pitcher added that the sector also needed to develop currently lacking ‘risk-proportionate guidance’, and equally needed to be able to respond to future and emerging risks. He concluded: “So, I hope I have given you an insight into some of the challenges with fire safety and the decarbonisation agenda. As I said at the start, we’re a long way from knowing all the answers; it is an evolving feast – but through forums like this, and everybody contributing, maybe we will have some answers going forward.” Here he thanked delegates for their attention, and invited questions.