Frequently asked questions
Where do I need CRI 95?
Where staff judge skin, tissue or blood closely: general lighting in operating theatres, recovery, examination and treatment rooms, dermatology, wound care, endoscopy and blood collection. EN 12464-1 asks for at least Ra 90 in these areas. CRI 95 versions give more margin, and a high R9 (saturated red) matters for blood and tissue. On wards, in corridors and in general areas, CRI above 80 meets the standard and is a little more efficient.
What are R9 and R13, and why do they matter?
They are two of the special colour rendering indices defined in CIE 13.3, which the headline Ra figure doesn't include. R9 is a saturated red: a low R9 makes blood and tissue look dull or brownish. R13 is a light skin tone, relevant wherever skin colour is assessed. For theatres and treatment rooms, look for high values of both. We quote what the manufacturer publishes and can send full colour rendering data where it is available.
Which colour temperature should I choose?
4000 K (neutral white) is the usual choice in operating theatres, examination and treatment rooms, intensive care and laboratories. 3000 K gives a warmer, calmer feel in patient rooms, day rooms and waiting areas. Keep one colour temperature across rooms where clinical judgements are made, so skin looks the same everywhere. Most of our CRI 95 panels are 4000 K only, and some luminaires have tunable-white versions from 2700 to 6500 K.
Do I need special lamps for observing cyanosis?
Cyanosis is the bluish tinge of skin and lips caused by low blood oxygen, and some light sources make it harder to see. The Australian and New Zealand standard AS/NZS 1680.2.5 sets a cyanosis observation index (COI) of no more than 3.3, with a colour temperature of about 3,300 to 5,300 K, where cyanosis must be detected. EN 12464-1 doesn't set a COI limit. Most LED datasheets don't publish COI, so ask us if your project needs it.
Do luminaires in operating theatres need to be IP65?
IP65 on the room side is the usual choice. It means the face is dust-tight and protected against water jets under IEC 60529, which suits frequent wet cleaning and disinfection. It also indicates a well-sealed luminaire, which helps the theatre hold its positive pressure. IP65 isn't an airtightness test, though, so the luminaire must also be sealed to the ceiling with a continuous gasket.
How does lighting work with laminar-flow or ultra-clean ventilation?
The air terminal or canopy over the operating table comes first and must not be interrupted. General lighting goes in a ring around it, or is built into the canopy edge by the canopy maker. Low, streamlined luminaires disturb the airflow less: our Rhenium continuous line and Hafnium luminaire have oval profiles designed for laminar-flow areas. In the UK, HTM 03-01 covers ultra-clean ventilation; in Germany, DIN 1946-4 covers operating room classes Ia and Ib.
How does a luminaire seal to the ceiling?
Recessed panels have a perimeter gasket between the luminaire frame and the ceiling, compressed as the luminaire is fixed. For a good seal, the cut-out must be accurate, the fixings tightened evenly and cable entries made with the glands supplied. If a luminaire is opened or removed, check the gasket and replace it if needed before refitting. In theatres and isolation rooms, an unsealed gap works against the pressure regime.
Will the luminaires withstand our disinfectants?
Glass faces and powder-coated or stainless steel bodies tolerate most hospital disinfectants, but no material resists every agent at every strength. Alcohols can craze PMMA, and chlorine-releasing agents can mark metals if left to dry. Send us your cleaning and disinfection schedule, with agents and strengths, and we'll ask the manufacturer to confirm compatibility for the body, diffuser, coating and gaskets. Where resistance isn't stated, we'll tell you.
Frameless or framed: which is better for infection control?
Frameless luminaires, such as Hypericum, Carbon, Achillea and Rosmarinus, have no frame or visible fixings between diffuser and body, so the face wipes clean in one stroke and there are fewer edges for residue. Framed luminaires can be just as well sealed, but the step between frame and diffuser is one more edge to clean. Frameless designs are often preferred in theatres; framed panels are widely used in treatment rooms and support areas.
Glass or PMMA diffuser?
Glass is harder, more scratch-resistant and tolerates more cleaning agents. Laminated glass stays in one piece if it breaks, which is useful over patients. Micro-prismatic PMMA controls glare well and is lighter, but it can scratch and can craze with some alcohols and solvents, so it is often supplied behind toughened glass. For theatres and heavily cleaned rooms, choose a glass face.
What does the bed-head unit include?
Our Arnica bed-head unit is a 1250 mm wall-mounted unit in white powder-coated steel. It gives reflected general light for the room, local light for examination and reading, and a night light. It also includes two 230 V sockets, three switches, data sockets and an equipotential socket, with connections for the call system. It is IP40 and IK04, in 3000 K or 4000 K with CRI above 80.
How do you avoid glare for patients lying in bed?
A patient on their back looks straight at the ceiling, so avoid bright luminaires directly above their eyes. Place ceiling luminaires over the foot of the bed or between beds, use reflected or indirect light for ambient lighting, and keep reading lights local. Low-glare optics help: Lavandula uses white reflectors behind toughened glass to limit glare for people lying beneath it, and Salvia includes an indirect rest light.
How should wards be lit at night?
Use a very low night light, at a level of a few lux, so staff can observe patients and move safely without waking them, with a separately switched observation light for closer checks. Bed-head units such as Arnica include a night light. Dim corridors to 50 lx, the EN 12464-1 night value, rather than switching them off, and stop corridor light spilling into rooms. In the UK, SLL Lighting Guide 2 gives detailed guidance.
How much light does each room need?
EN 12464-1 sets, for example, 1,000 lx at Ra 90 for general lighting in operating theatres, 500 lx at Ra 90 for examination rooms and for pre-op and recovery, 1,000 lx at Ra 90 for examination and treatment, 100 lx for general lighting on wards with 300 lx for reading, and 100 lx in corridors by day and 50 lx at night. Many clients have their own design guides, so check those too.
Are emergency versions available?
It depends on the product. Some can be supplied as self-contained emergency versions, others for connection to a central battery or safety supply. Ask us for your project and we'll confirm the options. In medical locations, IEC 60364-7-710 requires surgical luminaires and other essential theatre lighting to switch to the safety supply within 0.5 s, and other safety lighting within 15 s, so agree which luminaires need it early.
Can the luminaires be dimmed with DALI?
Many of our luminaires are available with on/off or DALI drivers, and each product page lists the options. DALI suits healthcare well: it allows scenes such as examination, rest, night and cleaning on wards, or a dimmed scene for endoscopic surgery, plus constant light output and links to a building management system. Some luminaires also have tunable-white versions on DALI.
What does "made in an ISO 13485 plant" mean?
ISO 13485 is a quality management system standard for organisations that design and make medical devices. It certifies the factory's processes, such as document control, traceability and risk management. It doesn't test the luminaire's light, sealing or cleanability, and it doesn't make the luminaire a medical device. Our luminaires are general lighting; Hypericum, Valeriana, Echinacea and Rosmarinus are made in a plant with an ISO 13485 quality system.
Do you supply operating lights?
No. Surgical lights and examination lights for diagnosis are medical devices, made to IEC 60601-2-41, and they are a separate product class. lumi medical supplies the general lighting of the theatre or treatment room around them, to EN 12464-1. We'll coordinate our layout with the surgical light and its mounting.
Why do product pages quote LED flux, not luminaire output?
Most of our product pages quote the LED flux the manufacturer publishes, usually at 4000 K. That's the light the LEDs produce before it passes through the diffuser. The luminaire's actual output is lower and depends on the diffuser chosen: glass, anti-reflective glass and PMMA options all absorb or redirect light differently. For design, use the photometric files or ask us, and we'll give luminaire output and calculate with it.
Can I get IES or LDT files?
Yes. Where a file isn't already on the product page, ask us and we'll send IES or LDT (EULUMDAT) files for the versions on your project, for use in DIALux, Relux and other design software. We can also run the calculations for you, using your ceiling and equipment layout.
Can I get samples, and what are lead times?
Where possible we can arrange samples, so you can check the finish, diffuser and colour rendering, and so your infection control team can try their cleaning agents. Lead times depend on the product, version and quantity, so we confirm them with each quotation. Tell us your programme early, especially for large projects or special versions, and we'll plan deliveries around it.
What should I send to start a project?
A room list with the use of each room, reflected ceiling plans showing surgical lights, ventilation and medical equipment, the ceiling system, the cleaning and disinfection regime and any client lighting design guide. If you only have part of this, send what you have and we'll work from there.
Planning a clinical space?
Send us the room layout, the room types or just a description. A lighting specialist replies within one working day.
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