In this Design Clinic we look at the design of a small hospital ward.
Hospitals are the most complex buildings that a lighting designer is ever likely to face. Hospital buildings vary enormously and the lighting has to be suitable both for the very busy medical staff and the prone, mainly inactive, patients.
Even within a general recovery ward, there are a great number of factors to be considered. The two main ones are glare to the patients and energy consumption. Glare is important because many patients do not (or cannot) move for hours at a time. A glare source that might seem quite minimal in an office can cause discomfort or even distress to a patient.
Hospitals are one of the few buildings that truly operate 24/7 every day of the year. As such, energy consumption is a very significant factor in the running costs of hospitals.
If you have never designed for hospitals, you might assume that every aspect of the lighting is tightly specified and there would be little choice as to the equipment or layout. Apart from a National Health Service document on lighting and colour, the most comprehensive, and most often quoted guidance, is the Society of Light and Lighting LG2 'Hospitals and Healthcare Buildings 2008'. The UK Department of Health also endorses LG2 for guidance on hospital lighting.
It is worth repeating words from the introduction to LG2: ‘The second and almost equally important consideration (of the lighting) will be to create an environment that is visually satisfying, wholly appropriate and ‘emotionally compatible’. Lighting can be a producer both of emotion and a sense of well-being’.
For the basic lighting, you need 300 lux on the bed and >100 lux between the beds and in the central ward area. This leads to many solutions that have a luminaire over each bed plus some general supplementary lighting.
The more demanding lighting requirements concern glare and the intensity of light towards the patients. This varies greatly depending on whether the luminaires are wall or ceiling mounted. It also depends on the exact geometry of the ward. Luminaires mounted on the opposite wall can often be a greater source of glare than those on the ceiling. You cannot design ward lighting without knowing where the beds are located.
For a variety of reasons, wall mounted luminaires should be 1.8m above floor level. There are strict intensity limits for luminaires mounted lower than this height.
Most wards have curtains around the bed and there is a requirement that the illumination level in these areas does not drop by more than 25 percent compared with when the curtains are opened. This tends to favour lighting above each bed but there are other advantages in having centrally mounted luminaires.
In terms of colour rendering, the recommendations are that all lighting in clinical areas should have a CRI of not less than 80 and have a CCT of 4,000K. In specialist areas such as those used for treatment or examination, CRI >90 is required. Note that this applies to the immediate task area and is usually provided by a dedicated fixed or mobile examination lamp.
All the options shown comfortably exceed illuminance requirements and, depending on the available daylight, they could easily be dimmed to save energy.
Our ward has plenty of daylight and a 3m ceiling.
The general lighting is produced by the new C90-R ceiling panel. This is a flush, IP55 recessed luminaire with the advantage of a smooth, wipe clean surface. It doesn’t have any nooks or ledges that could harbour dirt. One neat feature is that the frame for the diffuser is made in one piece and is only 12mm wide. This makes the frame invisible in the T-bar ceiling.
The micro-prismatic optic has a controlled cut-off at approximately 45°. This is useful in narrow wards or where precise beam control is required. The opal version optic is wider at 60° and other optics are also available.
The adjustable Carelite bed head luminaire has been specifically designed for use in multi-bed wards. It is available with different length outreach arms. The LEDs are positioned deep inside the reflector in order to avoid glare to other patients. Not only is it a reading light but the fixture also doubles as an examination light producing 2,000 lux at 0.6m and a CRI >90.
C90-R ceiling panel plus Carelite LED bed head light
Opal or micro-prismatic
This option again uses the C90 panels but the tunable white version on this occasion. We have followed the Glamox guidelines and used it with DALI control to vary the CCT from 3,00K to 6,000K with Ra 80.
The advantage of this type of scheme is that it can be fully automated to vary the illuminance and CCT throughout the day. Glamox recommend that if a ward contains elderly patients, the CCT should be 6,000K from 09.00 to 15.00 and then reduce to 3,000K thereafter. You can see that this scene is warmer than the other options. Glamox also recommend that if patients stay overnight, then the lighting should be programmed to produce an artificial sunrise (and sunset).
Elderly people require higher levels of illumination to do a task at an equivalent performance level of a younger person. Guidance as to how much you should increase the illuminance can be found in EN 12464.
C90-R recessed panel plus Carelite LED bed head light
LEDs 3,00K – 6,000K with Micro-prismatic panel
Aids bio-dynamic lighting
Here, again, the general lighting is provided by the C90-R. This time in combination with fixed bed head lights.
Above the bed is an A55-W wall mounted luminaire specifically designed for clinical areas. It fulfils the relevant lighting requirements of 'EN 60598-2-25 Luminaires for use in clinical areas of hospitals and healthcare buildings'. It is fitted, as standard, with 230V mains outlets and can also have data modules and emergency switches fitted. The LED version emits 5,600lm and has an acrylic diffuser, which directs the light both up and down. Interestingly, the top surface is deliberately slanted to ensure that cups or other objects that could topple cannot be placed on top.
C90-R ceiling panel plus A55-W bed head luminaire
Good for general hospital areas