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ANSI Z136.1-2007 section 4.3.10.2.2 provides a choice of three control methods for accommodating a class 4 laser area. The first two methods are known as "non-defeatable" and "defeatable" engineered safety controls. The third method, called the "procedural" method, is recommended if, and only if, the first two methods are not feasible or are inappropriate. The procedural method is not an engineered safety control and should only be used for laser systems in the medical field on a live patient where the laser is under the active control of a trained medical professional.
The links below provide a few case examples of the systems we typically provide to clients:
Figure 1 depicts a typical class 4 laser area utilizing non-defeatable engineered safety controls. Non-defeatable simply implies the interlock cannot be overridden for access. The entryway door is monitored by a safety circuit that shuts down the laser or closes a laser shutter if the door is opened. The system must be manually re-armed to resume operation.
Advantages:
- Highest level of safety
- Lowest cost
- Eliminates the need for laser curtains
Disadvantages:
- Only useful for supervised laser operation (Operator cannot exit room)
figure 1
figure 2
Figure 2 depicts a typical class 4 laser area utilizing defeatable engineered safety controls. This method of control permits unrestricted ingress and egress of qualified laser-trained workers while restricting access to untrained or unauthorized personnel.
Advantages:
- High level of safety
- Unrestricted access for qualified workers
- Informational electronic tone enunciation of door activity to warn of entry, exit, and door open timer
- Permits long term (hours, days, months...) experiments without interruption
- Laser can run unattended
Disadvantages:
- Curtain or appropriate beam block required to limit exposure at entryway to less than maximum permissible exposure during access
Your Engineered Laser Safety Solution
Products
Laser Safety Systems manufactures laser room interlock control systems with capabilities that include:
If you are ready to order, or simply want to discuss your application, please contact us.
We offer a short tutorial below describing the primary features associated with non-defeatable and defeatable access controls. If you seek additional information, you will find an in-depth tutorial accessed from our technical data page.
* Magnetic lock defeatable access control
* Electronic mortise latch (wireless) defeatable access control
* Electric Strike (used by card reader systems) activated defeatable access control
* Non-defeatable access monitors for doors and curtains