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for the sqfe use of lqsers - LIGO

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AMERICAN NATIONAL STANDARD 2I36.I-I986<br />

<strong>the</strong> immediate termination <strong>of</strong> <strong>the</strong> laser equipment in<br />

<strong>the</strong> event <strong>of</strong> equipment malfunction, audience unruliness,<br />

or o<strong>the</strong>r unsafe conditions.<br />

For training <strong>of</strong> operators see Section 5.<br />

4.5.1.2 Invisible Laser Emission Limitations.<br />

The general public shall not be exposed nor have<br />

access to laser radiation emission at wavelengths outside<br />

<strong>the</strong> visible range (0.4 to 0.7 pm) at levels<br />

exceeding <strong>the</strong> applicable MPE levels under any possible<br />

conditions <strong>of</strong> operation.<br />

4,5.1.3 Optical Radlatlon Limlts <strong>for</strong> <strong>the</strong> General<br />

Public. Laser radiation in <strong>the</strong> location where <strong>the</strong><br />

general public is normally allowed shall not exceed<br />

<strong>the</strong> applicable MPE levels during operation. hser<br />

radiation to be considered shall include reflections<br />

from all possible surfaces and scattering materials.<br />

4.5.1.4 Operator and Per<strong>for</strong>mers. Alt operators,<br />

per<strong>for</strong>mers and employees shall be able lo per<strong>for</strong>m<br />

<strong>the</strong>ir required functions without <strong>the</strong> need <strong>for</strong><br />

exposure to laser radiation levels in excess <strong>of</strong> <strong>the</strong><br />

applicable MPE level.<br />

4,5.1.5 Scanning Devices. Scanning devices,<br />

including rotating minored balls, shall incorporate a<br />

means to prevent laser emission if scan failure or<br />

o<strong>the</strong>r failure resulting in a change in ei<strong>the</strong>r scan velocity<br />

or amplitude would result in failure to fulfill <strong>the</strong><br />

criteria given in 4.5.1.3 and 4.5.1.4.<br />

4.5.1.6 Unsupervised Installaaions - Distanc€<br />

R€quirements. If a laser demonstration using<br />

a Class 2. Class 3a, Class 3b or Class 4 laser does not<br />

operate at all limes under <strong>the</strong> direct supervision or<br />

conhol <strong>of</strong> an experienced, trained operator, <strong>the</strong> laser<br />

radiation levels to which access can be gained shall<br />

be limited by baniers, windows, or o<strong>the</strong>r means so as<br />

not to exceed <strong>the</strong> limits <strong>of</strong> <strong>the</strong> applicable MPE. This<br />

limitation applies at any point less than 6 m above<br />

any surface upon which a penon in <strong>the</strong> general public<br />

is permitted to stand and to any point less than 2.5 m<br />

in lateral separation from any position where a person<br />

in <strong>the</strong> general public is permitted to be present du ng<br />

<strong>the</strong> per<strong>for</strong>mance or display. See Figures 2c, 2d and<br />

2e.<br />

4.5.1.7 Supervis€d Laser Installations. Laser<br />

demonstrations which do not meet <strong>the</strong> criteria stated<br />

in 4.5.1.6 shall be operated at all times under <strong>the</strong><br />

direct supervision or conrol <strong>of</strong> an experienced,<br />

trained operator who shall maintain constant surveillance<br />

<strong>of</strong> <strong>the</strong> laser display and terminate <strong>the</strong> laser<br />

emission in <strong>the</strong> event <strong>of</strong> equipment malfunction.<br />

audience unruliness or o<strong>the</strong>r unsafe conditions.<br />

18<br />

The operator shall have visual access to <strong>the</strong> entire<br />

area <strong>of</strong> concem. lf obstacles or size preclude visual<br />

access by <strong>the</strong> operator, <strong>the</strong>n multiple obsewers shall<br />

be <strong>use</strong>d, with a communication link to <strong>the</strong> operator,<br />

In such supervised installations accessible laser radiation<br />

shall be limited by baniers, windows or o<strong>the</strong>r<br />

means so as to not exceed <strong>the</strong> applicable MPE (see<br />

4.5.1) at any point unless <strong>the</strong> following requirements<br />

arc mer:<br />

(l ) The accessible laser radiation is maintained<br />

a minimum distance <strong>of</strong> 3.0 m above any sudace upon<br />

which <strong>the</strong> general public would be able to stand during<br />

a per<strong>for</strong>mance. See Figure 2d.<br />

(2) The accessible laser radiation is maintained<br />

a minimum distance <strong>of</strong> 2.5 m in lateral separation<br />

from any position where <strong>the</strong> general public is permitted<br />

to be prcsent during <strong>the</strong> per<strong>for</strong>mance or demonstration.<br />

See Figure 2e.<br />

As a general practice, <strong>the</strong> largest practical venical<br />

and lateral separation distances should be employed<br />

wherever possible. However, if specific physical limitations<br />

<strong>of</strong> <strong>the</strong> space in which <strong>the</strong> lasers are to be <strong>use</strong>d<br />

preclude compliance with <strong>the</strong> required minimum<br />

separations specified in (l) and (2), shorter separation<br />

distances may be utilized, provided that <strong>the</strong> LSO<br />

assures that altemative measurBs are established<br />

which assure an equivalent degree <strong>of</strong> protection to <strong>the</strong><br />

general public.<br />

4.5.1.8Beam Termination Requirements.<br />

All laser demonshation syslems shall be provided<br />

with a rcadily accessible means to effect immediate<br />

termination <strong>of</strong> <strong>the</strong> laser radiation. lf <strong>the</strong> demonstration<br />

does not require continuous supervision or<br />

operator control during its operation, <strong>the</strong>re must be a<br />

designated person at all times at <strong>the</strong> show or display<br />

who is responsible <strong>for</strong> <strong>the</strong> immediate termination <strong>of</strong><br />

<strong>the</strong> laser radiation in <strong>the</strong> event <strong>of</strong> equipment malfunction,<br />

audience unruliness or o<strong>the</strong>r unsafe cond.itions.<br />

45,1.9 Maximum Power Limitations. The<br />

maximum output power <strong>of</strong> <strong>the</strong> laser shall be limited<br />

to <strong>the</strong> level required to pmduce <strong>the</strong> desired and<br />

intended effect within <strong>the</strong> limitations outlined in<br />

4.5.1.1 through 4.5.1.8.<br />

4.5.1,10 Posting <strong>of</strong> Warning Signs and<br />

l-ogm. If <strong>the</strong> laser installation fulfills all requirements<br />

as detailed in 4.5.1.1 through 4.5.1.9 - or as<br />

altematively provided by <strong>the</strong> LSO (see, <strong>for</strong> example,<br />

4.5.1.7\ - <strong>the</strong>n posting <strong>of</strong> area waming signs shall<br />

not be required.

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