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SMC Laser Injury Event

Tekla A. Staley, CIH, CSP, CLSO 8th Annual DOE Laser Safety Officer Workshop Stanford Linear Accelerator Center September 2012

Idaho National Laboratory

SMC Laser Injury Event August, 2011

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Event Occurrence

An SMC technician received 2nd degree burns to the middle and ring fingers of

his left hand while performing a preventive maintenance (PM) procedure on a Class 4 industrial laser on August 30, 2011. The task required placement of a “target” in the beam path to verify

mirror alignment.

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Maintenance Prerequisites • Training

– Qualified electrician – Laser operator qualification – Vendor maintenance training

• Work Authorization – Approved work control document – LSO review and approval – POD

• Execution – Pre-job briefing

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Cincinnati CL707 Laser System

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Rofin DC035 Resonator Cabinet

sight glass

high voltage indicator

telescope Z-box

shutter

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Beam Formation and Z-Box

Z-Box

Slab

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Beam Direction within Z-Box

Spatial filter is upstream of the Z-box.

To beam dump/ shutter.

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Activity Hazard(s) Hazard Control(s) Remove, Inspect, Clean, & Replace mirrors.

High power, invisible infrared laser beam - serious skin and eye (corneal) burns can result from exposure to the direct infrared beam or a specular reflection of the beam.

Lockout/Tagout Using barriers and signs create a temporary LCA (Laser Controlled Area). Wear approved UVEX L208 Laser Safety Glasses when there is an exposed beam and within the Diffuse Reflection Nominal Hazard Zone. Never intentionally view the direct beam, even with laser safety glasses on.

Perform Cross Hair Burn, Check Laser Power and Adjustment. Remove and install cross hair alignment tool.

High power, invisible infrared laser beam - serious skin and eye (corneal) burns can result from exposure to the direct beam or a specular reflection of the beam. Eye and skin injuries may also result from exposure to diffuse infrared beam reflections within the diffuse reflection nominal hazard zone.

Authorized Maintenance Technician in control of the laser during all maintenance activities. Using barriers and signs create a temporary LCA (Laser Controlled Area). Adjust laser to low power. Craftsman must be aware of the hazardous infrared beam and keep all body parts clear of the beam path. Wear approved UVEX L208 Laser Safety Glasses when there is an exposed beam and within the Diffuse Reflection Nominal Hazard Zone. Never intentionally view the direct beam, even with laser safety glasses on. Keep body parts clear of the Diffuse Reflection Nominal Hazard Zone when there is an exposed infrared beam. The Diffuse Reflection Nominal Hazard Zones: Line 9 (3300 Watts with Laser head removed & unfocused infrared beam accessible) is 40.3 inches.

Work Order – Electrical 2000 Hr. Runtime PM

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Work Order – Electrical 2000 Hr. Runtime PM

26. Inspect the spatial filter assembly and beam absorber for coating damages. Check spatial filter alignment, adjust if necessary incl. mirror heating device? See (VA-19-01-24). See left side of traveler.

27. After replacing the special filter, perform a paper shot.

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Vendor-Provided Maintenance Procedures

Spatial Filter Adjustment

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Simmer State Power is supplied to the

slab electrodes. Power is sufficient to create

optical radiation. Energy is insufficient for

optical radiation to exit the diamond window as a beam. Theoretically, no beam is

present in the telescope. Input is needed from the

controls to ramp up to full power.

Z Box

Aperture Target #4

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CNC Laser Control

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Investigation - Failed Barriers • Training

– Interface between Rofin and Cincinnati equipment. – Simmer – Vendor training and refresher intervals

• Work Order Planning – Skill-of-the-craft – Gaps in work order – Vendor procedures not included

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Failed Barriers • Work Performance

– Performing work from memory – Recommended vendor practices not followed – Bad behavior reinforced by good consequence

• Hazard Analysis – Reliance on skill-of-the-craft – Expert-based vs. standards-based controls

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Recommendations • Perform an Extent of Condition analysis for all work that utilizes vendor

procedures. • Increase rigor in review of work order adequacy and appropriateness

of controls, including: – when laser safety glasses are necessary – matching tasks in the hazard assessment to tasks in the work

instructions. • Provide additional system training to maintenance technicians, system

engineer and S&H personnel. – Rofin and Cincinnati vendor training

• Perform management observations of all in-progress work • Issue a lessons learned

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Corrective Actions • Vendor training provided • Increased rigor in laser qualification program, including oral boards • Procedure/work order revisions

– Approval of alternate controls • Commitment to expectations for systems engineer and safety

professionals • Management observations • Extent of conditions analysis

– All laser maintenance activities – All high energy equipment

• Lessons learned

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A Word About CoHE • ORPS (NE-ID--BEA-SMC-2011-0012) classified as 2F(1) – Any

unexpected or unintended personal contact (burn, injury, etc.) with a hazardous energy source.

• NTS requires action and drove the 38 total corrective actions. • Alternate controls for tasks that are “routine, repetitive and integral” to the

use of the equipment for production (i.e. minor tool changes) • Determined that maintenance activities with respect to laser alignment

require “live” work and alternate controls. • Alternate controls include:

– Resonator door interlocks bypassed – PIC pendant control – Turning off HV vs. LOTO (turning off mains) – Validating status of HV with indicator lights, computer console – Physical check of shutter position – Physically checking for presence of beam with thermal paper

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Unfocused Beam Test

3100 Watt, unfocused, CO2, laser

beam fired at a pair of plano

safety glasses.

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