Laser Laboratory Design Guide LBNL Laser Safety Program- V1-2012 Things to consider & avoid



The opportunity to set up one�s lab is always a great occasion. In doing so, there are items one can easily overlook. The purpose of this guide is to provide guidance, reminders and explanations of items for you to consider in establishing or retrofitting your lab. Some items will be repeated from different vantage points within the guide.

Please send any comments or suggestion for the guide to the laser safety officer (LSO). A major tenet of the Laser Safety Program is to keep looking for ways to improve service to you the laser user.

Principal author: Ken Barat Intern: Justine Woo

Table of Contents

Section 1 Exterior Design 5

Access Control/Controlled Entry 5

Door Interlock System 5

Electronic Lock 5

Posting 6

Door Notes 6

Illuminated Warning Sign 6

Sign Conditions 7

Eyewear Storage 7

Storage Considerations 7

Windows 7

Window Options 7

Door Postings 8

Emergency Crash Off Switch 8

Section 2 Interior Layout 8

Optical Table 9

Before the Tables Arrive 9

The Optical Table is in Place 9

Which Way are the Beams Pointing? 9

Enclosures/Barriers 10

Perimeter Guard 10

Complete Table Barriers 10

Local Blocks- Beam Blocks 11

Beam Path Management 11

Shelves Over Tables 11

Work Station 11

Rack Unit 12

Curtain Area 12

Section 3A Environmental Factors: 12

Utilities 12

Temperature Control/Chillers 13

Ventilation 13

Vacuum Pumps 14

Lighting 14

Fire Safety & Controls 14

Electrical Power 15

Eyewash/Shower Station 16

Section 3B Interior-Institutional Items: 16

Space Around Electrical Panel 16

Seismic Bracing 16

Flooring 16

Storage (Chemicals, Flammable Liquids, Gases) 16

Storage Space for Supplies 17

Chemical storage 17

Gas Storage 17

Flammable Liquid Storage 18

Biological Storage 19

Radioactive Waste 20

Cryogen Use 20

Superconducting Magnet 20

Section 4�..Human Factors: 20

Walkway Spacing 20

Reach Issues 20

Workstation Locations 20

Storage Space 20

Wall units 21

Instrument Location 21

Section 5,,Abbreviated Checklist 21

Appendix A: Laboratory Lessons 24

Section 1 Exterior Design

This section details items to consider, when setting up your lab, that are on or related to the exterior of your lab. Remembering your lab is not just the inside.

Access Control/Controlled Entry:

Class 3B & Class 4 laser labs require access control. The laser chapter of Pub 3000 and the laser ANSI standard (Z136.1 & Z136.8), allow for a wide range of access controls. The three most common are: door interlock systems; an electronic lock; and/or posting. The system that should be chosen depends on how well the laser beams are contained. The LBNL LSO needs to be consulted to help make this determination. If a laser interlock system is required, it must be such that the interlock must be armed first to allow the laser to be turned on. An interlocked system is not always the best solution. Most importantly it does not protect the users, only those who should not be entering. Interlock systems must only cause the laser beam to become safe when tripped. This is often achieved by dropping a shutter or causing the laser to lose power (least favored approach).

Door Interlock System

  • The interlock must be armed to allow the laser to be turned on

  • An interlock system is not always the best solution

  • Non-defeatable door interlock is not a viable option. This type of system is designed to block the beam or drop power every time the door is opened.

  • Defeatable door interlock is set with an access device on the outside (i.e. key pad or card key reader) that allows authorized staff to enter. Triggering the device sets a pre- determined (15-30 second) bypass where the door can be open and the laser will stay on. Exiting is best controlled by a crash bar which triggers a pre-timed bypass.

    Electronic Lock

  • Cipher lock with key override: this approach provides secure access but has no effect on laser operation. The key override is for first responders only, not housekeeping.


    Posting Only-Administrative Access Control

    Can be allowed if the Class3B & or Class 4 laser system is in normal operation operating in a Class 1 or near Class 1 system configuration

    Door Notes

  • Standard door safety requirements

    • Self-closing device on door a must for laser labs

    • Standard keyed lock, should not be used, too many people have �master keys�

    • Doors to lab should not be fire-rated unless necessary

    • Fire resistant doors should have magnetic hold-open features

    • Door will close in event of an alarm

  • Egress doors

    • Crash-bar for easy egress

    • 36� or 42� wide doors

    • Doors opening onto exit corridors must swing with exit egress

    • Minimum clearance if 32� when door is open 90 degrees

    • Lab benches, equipment, furniture, etc. cannot be placed within 5� of egress

    • Doors within interior partitions must be self-latching


Illuminated Warning Sign

It is preferred that laser labs that contain a Class 3B or Class 4 laser have a visual indicator that the laser is in use. Once again, a review of beam containment during normal operation may void this requirement. The illuminated warning sign can be of several variations. The sign can solely indicate the laser is powered up or multi-modes such as safe, laser on, and beam accessible.


Figure 1: Laser Warning Sign Too High and Not Informative

Sign Conditions

  • Posted at eye level (60� or 152 cm above the floor) to the side of the entryway, not above the door frame

  • Low voltage rather than 110 Volts

  • LED light source rather than standard bulbs

  • A red light or non-descriptive sign is not sufficient

  • The illuminated sign is required for each doorway that is accessible

  • Illuminated whenever the laser is energized and capable of producing a beam

  • Automatic light, light turn off/on based on when the laser is on/off

  • If light manually controlled, light switch shall be located in a convenient position near the laser control

    Eyewear Storage

    A critical element of laser safety is laser protective eyewear; hence, the storage and protection of that eyewear is very important. Laser eyewear can be stored inside or outside of the laser use area or at both locations. The storage device must protect the physical integrity of the eyewear and be easily accessible to the


    Storage Considerations


    Figure 2: Eyewear Being Stored on Interior of Door

  • The storage device must protect the physical integrity of the eyewear, protect from scratches and stored in clean and sanitary �Ready for use� condition, keeping away from dust, dirt or other contaminants.

  • Prolonged exposure to ultraviolet radiation can degrade laser protective eyewear, in particular laser eyewear with high optical densities.

  • Remove damaged eyewear from storage holder i.e. broken temples, scratches that would render it unsafe to use, burn marks, etc.

  • Eyewear with worn off labeling is not allowed to be used; it is advisable to replace

    manufacturer labeling with one�s own or post image of eyewear and labeling at storage location.

  • Store in a way to avoid confusing different types of eyewear that may be used

  • A good practice is to store alignment eyewear separately from other eyewear at the lab

  • Store separately standard non laser safety glasses to ensure they are not confused with laser protective eyewear,

  • Wall pouch holder, can be obtained from LSO as well as vendor list of commercial eyewear holders.


    As a rule, windows into the typical laser lab are not a good idea and doors should not be equipped with such. If doors are equipped with windows, the following needs to be considered:

  • Window panels in doors should be covered with an permanent opaque material

  • If windows are required for non-laser use periods, then shades or removable covers for laser operation need to be available

  • Electronic shutter windows can be used in some circumstances

  • Windows can be covered with optical density acrylics to provide protection and viewing. Such acrylics must be labeled with wavelength and optical density.

  • Portals/viewing windows must be designed to prevent any exposure above the maximum permissible exposure value.

  • Wall windows should be treated the same as door windows.

Door Postings

Any laboratory using a Class 3B and or Class 4 laser is required to have a hazard communication posting. This can be a sole ANSI laser warning sign or the ANSI warning sign in combination with the standard chemical hazard communication sign. Each can be obtained from the LSO or appropriate Division Safety Coordinator.

  • The ANSI required warning information must be on the posted sign:

    • Highest class laser in use

    • Signal word (Warning or Danger)

    • Wavelengths in use

    • Optical Density for wavelengths

  • The door posting should also contain the following:

    • Alert of hazards

    • List of authorized users and emergency contact numbers

    • Instruction on entry

Emergency Crash-Off Switch

LBNL policy does not require a button (commonly seen as red mushroom button) for a Class 3B or Class 4 lab. It is suggested by the ANSI standard; equivalent devices are acceptable, such as posting the location of the circuit breaker box that controls the lasers or the location of the laser power supplies in the room. Most commercial

interlock systems include this crash off device. Some labs locate this switch inside the lab or both inside & outside.


Figure 3: Labeled Emergency Stop

Section 2 Interior Layout

This section details interior items to consider when setting up your lab. There is more to consider than where the wine rack or cappuccino machine goes.Remember it is best to have all room construction completed before the optical table is put into place.

Optical Table

The optical table is the place where your experimental action will take place and how it is laid out is of extreme importance to you because it directly affects your success. While your mind is spinning experimentally, there are additional items to consider.

Before the Tables Arrive

  • Scanning the floor: get scanned for wires and cables under and within the floor (remember floor scanning results are only good for so long before they expire).

  • Penetration permit will be required to install table legs

    • Contact Riggers to schedule installation

  • Consider seismic system for the table:

    • Can this be provided by the vendor or will it have to be LBNL engineered?

  • Determine how much power you will need for experimental equipment

    • See Section 3 Environmental Factors:

  • How tables will fit into the room, when you consider institutional clearance from electrical panels, etc See Section 3A & 3B for details

  • Will shelves be required above the optical table?

    • If yes, make sure equipment fits under the shelves. Determine height of equipment including addition of cameras, and then determine height of shelves over table.


  • Laser Exclusion zone (laser free area)

    • Some users set up a curtained or blocked off area right inside the entry point of the lab. This establishes a laser-free zone. LBNL laser safety program protocol is no optics can be seen from open doorway.

      The Optical Table is in Place

      OK, the table(s) has arrived and has been put into place, now you have to consider

  • Seismic Bracing � anchor, support, brace

    to building structure: will it be obtained from the vendor or lab designed, built and installed?

  • The tables will need to be grounded

  • Laser exclusion zone

    Figure 4: Flat Screen Hanging from Over Table Shelf

    • Some users set up a curtained or blocked off area right inside the entry point of the lab; this establishes a laser-free zone

  • LBNL laser safety program protocol states no optics shall be seen from open doorway.

    Which Way are the Beams Pointing?

    A good practice in laser safety is to not have the beam path pointing towards doorways.

    This can be implemented with the use of barriers around the optical table or at the end facing the entry way.

    Can the laser set up be positioned towards the back of the room, rather than right near the entry way?

    The LBNL standard approach is for one not to be able to see optics from outside the doorway. Many types of enclosures can provide compliance with this approach. Types of enclosures close to beam or optical path that provides the best protection are listed below.


    Depending on the experimental set up, several means of beam containment are open to the user. One is walls around the set up. The enclosure needs to be at least several inches higher than intended beam path:

    Perimeter Guard

    Plastic Laser Enclosures

    Figure 5: Cover Optics and Beam Tubes


  • These should be rated for your wavelengths and required optical density Have a diffuse interior surface to promote diffuse reflections from any stray beams.

  • Available from a number of vendors as kits

  • Can be self-tested, using spectrometer/power meter

  • Plastic laser enclosure covers

    • Covers will provide a cleaner work area

    • Contain reflections

    • Negative impact: can quickly become a shelf and maybe be difficult to remove

      Metal Laser Enclosures- Wavelength & optical density determination not a concern

  • Should have an diffuse pattern on the inside surface

  • Beware of the intensity of your beams, metal coatings can be ablated off, yielding a specular surface.

    • Commercial units generally come in 12� and 18 � heights

    • Homemade enclosures have no such limitation, but often need to be anodized (which LBNL can do for you)

  • Metal laser enclosure covers

    • Covers will provide a cleaner work area

    • Contain reflections

    • Negative impact: can quickly become a shelf and maybe be difficult to remove


      Complete Table Barriers

      These units are 80/20 frames or uni-strut that stand a few inches off from the optical table and have a track for panels (most commonly sliding panels). Frame can be equipped with HEPA Filters, lights or no roof at all.

      Figure 6: Complete Table Barrier 10

  • Around entire table or portion of it

  • Can be open or closed on top

  • May need task lighting

  • Items stored on top must be seismically braced

    Local Blocks- Beam Blocks

    Even with the use of perimeter guards and other barriers, the use of beam blocks is recommended. It is an absolute must when the table is an all open beam path. Their function is to block stray reflections/beams.

    Beam Path Management

  • Enclosures should be compatible with laser wavelength and beam power.

  • Laser enclosures, beam stops, beam barriers and other exposed surfaces shall be diffusedly reflective at laser wavelength used

    • Surfaces that create specular reflection cannot be used

    • Materials used for beam stops or beam barriers shall not off-gas or be combustible at the beam power used