GENERAL
The
laser is a light source that produces a monochromatic coherent
beam of relatively high energy. In addition to the potential hazards
of eye or body exposure to the laser beam and its reflections,
potentially harmful radiation may be generated. Ozone may be produced
and toxic materials may be generated in the target area. Precautions
are also required to protect against exposure to high voltages
and the possibility of fire. (toxic gases are often used in laser)
This procedure outlines basic safety
considerations for laser operations. The procedure is based on but
is not as inclusive as the American National Standards Institute
(ANSI) Standard Z136.1 - 1972 and the New York Labor Department Code
Rule 50. It is recommended that faculty and staff working with lasers
be thoroughly familiar with these two codes.
EXPOSURE CRITERIA
Because the energy level and output
frequency or wave length depend upon the type of laser used and
its method of operation, the radiant intensity of each laser beam
and of its reflections shall be determined by direct measurement
or by calculations. Control measures shall be taken to keep the
possible exposure of personnel well within the maximum permissible
exposure (MPE) levels stated in ANSI Z136.1 and Code Rule 50.
NOTIFICATION
The University Radiological Safety
Committee must be notified prior to the procurement, construction,
or initial operation of laser equipment. The Committee shall review
all equipment, installations, and operating prior to initial operations.
The department owning and operating the laser shall notify the Environmental
Health and Safety (EHS) Office of such installations and will ensure
that governmental agencies are notified and maintain required records.
The EHS Office must be notified
when a laser operation is discontinued or dismantled.
INVENTORY
The individual offices shall maintain
a current inventory of all laser devices. The inventory shall
include the manufacturer's name, model number, type, serial number,
SUNY inventory number, wave length, power and/or energy, beam
geometry, location (building and room), responsible faculty, and
users. A copy of this inventory must be sent to EH&S and updated
annually.
TRAINING
Faculty, staff, and students that
operate or assist in the operation of laser equipment shall be thoroughly
trained. The training shall include an explanation of potential hazards
of the laser beam and its reflected energy, safety requirements,
use of personal protective equipment, emergency procedures, and any
other information operators need to know in order to protect themselves
and others. Each operator should be given a copy of the operating
procedures. All faculty, staff, and students shall receive the required
training prior to operating the laser. Copies of emergency procedures
will be sent to the EHS Office for safety and security personnel
training.
EYE PROTECTION
Appropriate eye protection shall
be used whenever the possibility exists for eye exposure in excess
of maximum permissible limits. It shall be capable of attenuating
the maximum possible exposure to within acceptable limits. All eye
protection devices shall be clearly marked to identify the optical
density at the wavelength they will protect against. The owner of
the equipment shall conduct periodic inspections of this equipment
including inspection of attenuator material for pitting, crazing,
cracking, etc., and of frames for mechanical integrity and light
leaks. There shall be a sufficient number of eye protection devices
located in each laboratory containing a laser for all persons required
to be in the laboratory at any one time.
LABORATORY FACILITIES
Laser operations shall be confined
to fully enclosed rooms, isolated from other non-laser operations,
unless the laser equipment protects personnel from levels of radiation
above the MPE's indicated in ANSI Z136.1 and Code Rule 50. If more
than one laser is within a single room, effective optical and physical
barriers shall be provided between them to prevent personnel from
inadvertently viewing or intercepting beam paths. The use of door
interlocks and/or signal lights prevent entrance while a laser is
in operation shall be considered.
Laser beams shall not be projected
beyond the confines of the controlled area without prior written
approval of the University Radiological Safety Committee and the
EHS Office.
WARNING SIGNS
Laser warning signs shall be used
in accordance with ANSI Z136.1 and Code Rule 50. The presence
of warning signs should be checked daily by the owner/operator.
VENTILATION
Ventilation shall be sufficient
to remove any hazardous gases which may escape from sealed systems
of continuous flow gas lasers or to safely controlled cryogenic liquids
and gases used to purge and cool lasers.
Forced ventilation shall be provided
for pumping sources such as mercury or xenon lamps, which may produce
ozone in hazardous quantities. Forced ventilation will also be required
in the area of the target when toxic materials, such as evaporated
metals or decomposed materials are present.
Physical Facilities staff will be
consulted in all cases where additional forced ventilation is required
so as to assure adequate makeup air.
FIRE PREVENTION
Combustible and flammable material
will be kept to a minimum and placed so it will not be accidentally
exposed to high power laser beams. The EHS Office will assist in
the placement of appropriate fire extinguishers.
ACCIDENT REPORTS
Accidents involving exposure to a
laser beam shall be immediately reported to both the University
Health Physicist and the EHS Office. A written accident report
shall be completed by the injured person's supervisor and forwarded
to the EHS Office within five days.
All students receiving accidental
exposures must seek medical care immediately.
The following constitutes accidental
exposure:
1. A
person who suspects he has had accidental eye exposure or who suffers
persistent after-image or abnormal effect shall report to a medical
facility for examination.
2. A
person who receives skin exposure from a laser resulting in discomfort
or which produces a reddening of the exposed area shall report to a
medical facility for examination. Any delayed, persistent, or progressive
change in any area of the skin shall be reported.
OTHER REQUIREMENTS
1.
All laser installations shall meet requirements set forth in the
New York State Building Construction Code and the National Electrical
Code.
2.
High voltage laser circuits shall be protected by interlocked
covers. When the removal of interlocked covers becomes necessary
for work, such work, such as maintenance, adjustment or experimental
tryout, there must be a written procedure. The procedure will
outline the steps to be taken, precautionary measures, protective
equipment and type and placement of shielding and must be approved
by the faculty member responsible for the laser. A copy of such
procedure will be sent to the EHS Office.
3.
Capacitors shall be equipped with positive discharge devices and
the capacitor bank will be provided with adequate shielding for
protection in the event of rupture.
4.
Cables between the power supply and the laser head must be corona-free
and they must have adequate dielectric strength. Periodic inspection
will be made to determine these capabilities. If a cable shows
the presence of corona, it will be replaced immediately.
5.
Layout of all auxiliary equipment such as meters and instruments
will be made to minimize the hazards to the operators. For example,
operators will not be required to face the direction of the laser
beam during charging or firing in order to use the above instruments.
6.
High voltage vacuum tubes in power supplies rated over 10KV will
be surveyed on a regular basis for possible X-ray emission by
the owner/operator.
7. The beam path shall be enclosed wherever possible to avoid
accidental skin or eye exposure.
