Overheating in retirement homes. Reducing overheating in hot corridors through natural ventilation

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1 Overheating in retirement homes Reducing overheating in hot corridors through natural ventilation

2 For years building regulations have been encouraging warm, energy-efficient properties to serve the UK and its oft-chilly climes. But there is a flip-side to some of these targets as modern methods of building appear to be leading to overheating within structures; a problem that will only be exacerbated as climate follows its apparent warming trend. Whilst newly constructed houses are characterised by reduced heat losses and, hence, increased thermal efficiency during winter, they may not be suitably designed to cope with extreme heat events. A number of studies have identified that an unintended consequence of high insulation and air tightness standards of newly built and retrofitted houses may be overheating. Generally thermal mass coupled with night cooling through ventilation has been identified as a relatively effective measure to combat domestic overheating. Investigation into Overheating in Homes, by Department for Communities and Local Government Expert opinions Robust solutions are... needed for minimising heat gains in all future designs, and adaptation of such solutions for application to the existing stock, including reducing heat gains from communal heating systems The Building Regulations, over the past few iterations, have begun to acknowledge the need for ventilation as a means of heat removal. Overheating in new homes - NF 46, by NHBC Foundation

3 Overheating in residential care homes What causes overheating? What are the risks? As you can imagine, overheating is especially dangerous where society s most vulnerable are concerned. Worryingly, the Preventing Overheating document by the Good Homes Alliance states that 30% of instances of overheating recorded in the study occurred in flats and elderly care homes built after The Health Protection Agency has linked excessive heat to mental health complications, stroke, and heart attacks, while in 2003 there were 700 deaths as a result of heat waves, it continues. This document also identifies 25 C as the trigger point where mortality increases and there is an increase in strokes. In addition, the Investigation into Overheating in Homes, by the Department for Communities and Local Government, states: studies suggest that there may be typically around 2,000 deaths brought forward per year due to heat, compared to around 25,000 due to cold. However climate change projections suggest the heat related deaths could rise to around 5,000 per year in the 2080s if action is not taken. Aside from offering direction to future building designs, these figures show the dire need for proper temperature reporting in residential care homes, with appropriate action being taken as soon as possible to ensure the safety of residents. There are several recognised potential causes of overheating outside the direct presence or behaviour of residents: Solar gains through building fabric Solar gains through windows High external air temperature Building micro-environment Improved airtightness (latest Part L) Inadequate ventilation Centralised heating Especially relevant to the remit of this document is the issue of overheating in communal areas; what are becoming colloquially known as hot corridors. In these instances the routing of heating services through corridor spaces can be a major contributing factor; a modern design foible with unexpected and potentially hazardous consequences.

4 Products used in natural ventilation The ventilation solution Chain actuator Vent window Louvre The most cost-effective way of installing natural ventilation is at the construction stage, but there are a lot of care homes already built that are suffering from hot corridor problems. Retrofitting existing buildings needs to be done in the most costeffective way possible; we all know that if it s financially unviable then it simply won t happen. One of the most costeffective methods of cooling a building is by taking advantage of systems that already exist on site, a great example being the presence of standard windows. By adapting these to operate automatically via a dedicated control system, the airflow in a corridor can be controlled in relation to its temperature. Similarly, an existing smoke control ventilation system either natural or mechanical can be updated to enable dayto-day environmental comfort ventilation, without the need for drastic remedial works. Temperature sensor Wind sensor Control panel

5 Alrewych Court case study Alrewych Court is a 53- flat extra care retirement village in Walsall that was found to be experiencing corridor overheating deemed a potential risk to residents at times recording temperatures in the high 30s. SCS was introduced to the client by M&E contractor Regal to devise a solution; Regal addressed an issue of over-specified lighting while SCS devised a ventilation system to introduce air movement and release the remaining heat build up. For efficiency, the system included a smoke control function and utilised existing windows on site (that were previously opened manually) to create an automated environmental control system. SCS suggested using temperature criteria from CIBSE, to achieve no more than 1% of time (88hrs per year) over 28 C; thermal modelling confirmed our proposal would meet this criteria. Because the temperatures were so high and there was a client focus on the solution being worth the investment, we provided a modem and aerial for remote support via our SCS Eyeball system enabling us to work with the customer after installation to optimise the best set points. We also logged temperature data post-install so we could adjust operating points and ensure the best ventilation solution. We provided temperature sensors and key switch overrides to ensure there could be no unauthorised use of the system which could affect performance. Natural ventilation in action LOFT SPACE Eyeball Modem unit COMMON STAIRWELL CORRIDOR COMMON STAIRWELL CORRIDOR COMMON STAIRWELL Interface unit GROUND FIRST SECOND T4 T2 T1 Interface unit Main control unit T5 T3 Temperature sensor Actuated window T6

6 Alrewych Court case study From previous temperatures recorded in the high 30s, the performance and success of SCS Group s natural corridor ventilation solution has been proven via a rigorous data logging programme which reveals a temperature variation of less than 7.5 C at its most extreme. As can be seen from the graphs generated from data from the building s temperature sensors, the corridors experience very little variation in temperature in a daynight cycle, or indeed over a period of weeks. The reduction in average corridor temperature ensures the ongoing health and wellbeing of residents in the building, and proves the system as suitable for rolling out across similar retrofit (and new build) projects in the care home market. Temp in deg.c Before SCS intervention Average temperature was recorded at 35 C+ Temperature variation over time in naturally ventilated corridor (sensor T2) /18/2013 8/28/2013 9/08/2013 9/18/2013 9/29/2013 AFTER SCS intervention - natural ventilation Average temperature was recorded at C

7 Building Automation Support Easivent Contact us t e. w. Capital Business Park Parkway Cardiff CF3 2PZ 120 Pall Mall London SW1Y 5EA 303 Old Barn Farm Road Woolsbridge Industrial Park Three Legged Cross Wimborne BH21 6SP The Innovation Centre 1 Devon Way Longbridge Technology Park Birmingham B31 2TS SCS Group Alrewych Court v1 Oct 14