Brendan
Whether this is a cause for concern or not will depend on what wearing the
glasses is intended to achieve.
If an assessment of the reasonably foreseeable worst case exposure
conditions includes a laser beam (above the maximum permissible exposure)
striking from below then obviously they are not adequate. Full goggles would
be more appropriate under these circumstances. There is increasing concern
over off-axis exposures to optical radiation - but the concern is (I
understand) wavelength dependent.
An actual assessment of the above exposure conditions may demonstrate that
the glasses are only provided for reassurance. Under these circumstances the
additional risk due to the gap may be tolerable.
Dr John O'Hagan
Group Leader, Laser Dosimetry Group
National Radiological Protection Board
Chilton
Didcot
Oxfordshire
OX11 0RQ
UK
Tel: +44 (0)1235 822673; Fax: +44 (0)1235 822650
-----Original Message-----
From: Tuohy, Brendan, UCHG [mailto:[log in to unmask]]
Sent: 16 July 2002 13:25
To: [log in to unmask]
Subject: Laser safety glasses
Hi,
A pair of laser safety glasses manufactured by lasermet Ltd.(USA), have been
sent by a member of staff for my attention. They are concerned that there
is an opening between 0.5 and 1 cm, at the bottom of the glasses between the
frame and the contour of the face. Would you consider this to be a cause
for concern?
Thank you,
Brendan
___________________________________________________
Brendan Tuohy, Principal Physicist, Dept. of Medical Physics and
Bioengineering, University College Hospital, Newcastle Rd., Galway, Ireland
Tel: +353-91-544769/544770; Fax: +353-91-583017
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