Design Criteria for Flexible Design Criteria for Flexible Laser Safety Barriers...Laser Safety Barriers...used in the industrial laser environmentused in the industrial laser environment

Design Criteria for Flexible Design Criteria for Flexible Laser Safety Barriers...Laser Safety Barriers...used in the industrial laser environmentused in the industrial laser environment

Ryan F. HemmerleJay ParkinsonR. James Rockwell, Jr.Rockwell Laser Industries

The most commonly asked The most commonly asked questions...questions...

What is special about a “Laser Barrier”? When are laser barriers necessary? What options are available? What type of signs/labels are needed? Is the highest rating always needed? Can barriers be interlocked to the laser? What are the economics? (Is it cheaper to just

build walls?)

Lets Review ANSI..Lets Review ANSI....

“Where safety latches or interlocks are not feasible… One alternative is:

A door, blocking barrier, screen, curtains, etc. shall be used to block, screen or attenuate the laser radiation at the entryway.” ANSI Z136.1 4.3.10.2 (3)b

Total Hazard Evaluation...Total Hazard Evaluation...

“Such laser barriers shall be specifically selected to withstand direct and diffusely scattered beams. In this case, the barrier shall exhibit a damage threshold for beam penetration for a specific exposure time commensurate with the total hazard evaluation for the facility and specific application” ANSI Z136.1 Section 4.6.4

When are Laser Barriers When are Laser Barriers Necessary?Necessary?

To establish a permanent enclosure around a Class 3b or Class 4 Controlled area

Where conventional walls or windows would impede the manufacturing process

When the laser area may be frequently moved or repositioned to a new area

Efficiency and safety during times of maintenence and service…(Time is money)

Laser Protective Barriers for Laser Protective Barriers for Clean Room EnvironmentsClean Room Environments

Laser Protective Barriers Laser Protective Barriers Using Ceiling Mount DesignUsing Ceiling Mount Design

Laser Protective Barriers Laser Protective Barriers Using Floor Mount DesignUsing Floor Mount Design

Laser Protective Barriers Laser Protective Barriers With Interlocking FeaturesWith Interlocking Features

Objective: Objective: To Establish a Protocol For To Establish a Protocol For Choosing a Barrier Choosing a Barrier

Main items required... Laser parameters needed to determine barrier

threshold specifications Facility conditions during use:

Operation - Maintenance - Service The barrier mounting options:

Ceiling - Floor - Movable Frame The integration of entryway controls and

protective windows

Typical User RequirementsTypical User Requirements

Cost effective alternatives to permanent on-site construction

Compliance with ANSI Z136.1 and OSHA Design flexiblity for changing demands Temporary and/or permanent area safety

What Options are Available?What Options are Available?

Mounting Configuration Ceiling mounted track hardware Moveable floor frames

Clean Room computability Low particulate generation Anti-Static compatibility Washability

More Options...More Options...

Interlocks Infrared photo-trancevers wired to alarms hard-wired into laser system

Protective Window Films Wavelength dependant

Sinage and Labeling Compliance with ANSI and OSHA

Protective Barrier Labeling….Protective Barrier Labeling….

Proposed language for the “new” ANSI

Z136.1 Standard:

“ All laser protective barriers shall be labeled with the barrier threshold limit (BTL) and exposure time for which the limit applies and the beam exposure conditions under which protection is afforded.”

Proposed ANSI Z136.1 4.6.5.4

TYPICAL LASER BARRIER TYPICAL LASER BARRIER BTL TESTINGBTL TESTING

Laser barrier test showing various test spots Laser barrier test showing various test spots at different radiant exposure levelsat different radiant exposure levels

Laser Protective BarrierLaser Protective BarrierPenetration Threshold levels for four different barriersPenetration Threshold levels for four different barriers

Laser Beam Diameter (mm)Laser Beam Diameter (mm)

Irra

dia

nce

(W

cmIr

rad

ian

ce (

Wcm

22 ))

PTLPTL

300 W/cm300 W/cm22

200 W/cm200 W/cm22

100 W/cm100 W/cm22

PTL criteria setPTL criteria set

at a 5 mm beam at a 5 mm beam

diameterdiameter

2 W/cm2 W/cm22

Nd:YAG Laser @ 1064 nm & Argon Laser @ 514 nm for Nd:YAG Laser @ 1064 nm & Argon Laser @ 514 nm for 100 s.100 s.

Protective Barrier Labeling:Protective Barrier Labeling:A Suggested Format…A Suggested Format…

Barrier Model No. Exposure criteria Care and cleaning Laser exposure time,

BTL & Beam size specifications

Manufacturer ID

Other Typical User Other Typical User Requirements...Requirements...

Need for convenient barrier Storage “Complete” beam Containment Converting a Class 4 Controlled Area

into a Class 1 Area Maintenance and Service options Special Environments (ie: clean room,

medical, heavy industry…)

LPB CHECKLIST...LPB CHECKLIST... INSTALLATION ANALYSISINSTALLATION ANALYSIS

Application of laser:

Beam access possible in operation? Y/N Comments:

Beam access possible in maintenance? Y/N Comments:

CHECKLISTBARRIER MOUNTING INSTALLATION

Floor Frames: Gusset Strips: Ceiling Mount: Connection Strips Interlocking: Latch/Jamb:

Windows: Clean Room: Particulates: Anti-Static: Warning Signs:

Items to consider...

BTL GEOMETRIESBTL GEOMETRIES

FIBEROPTIC

LENS-ON-LASERINTRABEAM

Each case is defined by the application:

CHECKLISTLASER PARAMETER DATA:

LASER PARAMETERS

Laser type:______________________________________________Class: _______________________________________

Wavelength(s): ______________________________________ (m)Beam divergence: ________________________(mrad)

(see ill A # 1)

Beam diameter at exit of laser: __________________________(mm)

CHECKLISTLASER PARAMETER DATA:

OPERATION MODE

Pulsed ( ) Continuous Wave ( )

Pulse energy: __________________________________________(J)Maximum Average Power: __________________ (W)

Pulse length: _______________________________________ (sec.)

Repetition rate: _____________________________________(Hertz)

CHECKLISTLASER PARAMETER DATA:

DELIVERY OPTICS

Beam conduit ( ) Fiber optics ( )

Beam diameter just prior to lens: ________________________ (mm)Fiber optic numerical aperture:___________________

(see ill. B #3) (see ill. C # 5)

Focusing lens: focal length: ____________________________ (mm)Cone angle:___________________________(degrees) (see ill. C #6) (see ill. C #6)

CHECKLISTLASER PARAMETER DATA:

SYSTEM DESIGN & GEOMETRICAL FACTORS

Worse case viewing distance (diffuse targets): ___________________________ (in)

Nominal distance(s) from laser aperture to barrier: max: __________________ (feet) min: _____________________ (feet)

Choosing a Laser Protective Choosing a Laser Protective Barrier….Barrier….

1. Establish whether a conventional enclosure (walls or housing) is appropriate and will not impede the laser use

2. Establish whether a permanent or removable enclosure is required

3. Establish the features desired (dimensions, style, interlocking…etc.

Choosing a Laser Protective Choosing a Laser Protective Barrier….Barrier….

4. Evaluate the laser parameters and BTL

5. Determine the Installation requirements (ie: Floor Frames, Gusset Strips, Ceiling Mount, Connection Strips, Interlocking, Latch/Jamb…etc.)

6. Determine special requirements: (ie: Windows, Clean Room, Particulates, Anti-Static, Warning Signs…etc.)

SUMMARY….SUMMARY….

Laser barriers can provide special area protection that is MOVEABLE and/or PERMANENTand still provide area safety

Laser barriers are most often necessary when FLEXIBILITY and SPEED is needed for the laser installation

CEILING and FLOOR mounted units are available

SUMMARY….SUMMARY….

Laser protective barriers come in different BTL ratings for different user needs

Barriers can easily be interlocked to the laser Barriers are not inexpensive - but are usually

LESS expensive that building solid, permanent walls around the laser installation

Standard ansi-based signs/labels are recommended