Joachim

We have always specified a UV max of 75µW/lumen (which equals 3.75mW/m2 at 50 lux or 15mW/m2 at 200 lux) together with an overall light level in lux.

According to our Conservation Scientist, David Thickett: "The 75 micro watt per lumen threshold was specified by Thomsen (I think, certainly popularised by him) as the best available, reasonably priced  technology at that time (Tungsten halogen lamps).  Lamps are now available with UV contents of essentially zero.  I'm thinking about this at the moment, the big issue is the cost benefit with regards to the UV films for windows, some of which drop to 75 over maybe ten years"

There is also the question as to whether we should be specifying a maximum for lux hours/year rather than a simple lux level.

Trevor Reynolds
Collections Registrar, English Heritage, Room 530, 23 Savile Row, London W1S 2ET, United Kingdom
Tel: +44 (0) 20 7973 3482  Fax: +44 (0) 20 7973 3209

> -----Original Message-----
> From: Museum discussion list [mailto:[log in to unmask]] On
> Behalf Of Prevart GmbH
> Sent: 02 May 2005 18:30
> To: [log in to unmask]
> Subject: UV thresholds / policy in museums
> 
> Dear list,
> 
> In the last few years there has been extensive developpement in museum
> lighting as well as thresholds for UV seem to have been lowered
> considerably from 25mW/m2 to as low as 1mW/m2 in certain publications.
> Is there a concensus about the UV policy in museums? I would be
> interested in any opinions or recent research on this topic.
> 
> Joachim Huber
> Prevart GmbH - Konzepte für die Kulturgütererhaltung
> CH-8405 Winterthur (Switzerland)
> www.prevart.ch
> 

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