Laser Safety Flashcards
What are the two primary legislation for health and safety?
Health and safety at work Act 1974 (inspectors, legal duty as far as is reasonably practicable to health and safety of all employees) and the Consumer Protection Act 1987(producers are strictly liable for all defective products). Have to prove that it is safe.
What are three secondary legislations for essential health and safety requirements?
The Supply of Machinery (Safety) Regulations 2008, SI 2008/1597
- laser equipment must be designed and constructed in a way to prevent any accidental radiation
-no health risk should be created by laser radiation
The Provision and Use of Work Equipment Regulations 1998, SI 1998/2306
-Take measures as to reasonably practicable to control hazards
The Control of Artificial Optical Radiation at Work Regulations 2010, SI 2010/1140
-Exposure limit values (ELVs) are set
-must assess risk to eyes and skin
-carry out assessment for laser radiation in regard to above
The General Product Safety Regulations 2005, SI 2005/1803
-no product should be on the market unless the product is ruled safe.
How to assess exposure and risk for control of artificial optical radiation at work regulations?
Measurement/calculation of exposures
* competent services/persons
* suitable intervals
Consider:
* level, wavelength, and duration of exposure
* sensitive risk groups
* interactions with photosensitising chemicals
* indirect effects (temporary blinding, fire, etc)
* multiple sources
* classification (eg class 3B or 4 lasers)
What is the hierarchy of controls for the laser?
Elimination -> substitution(alternate working methods) -> engineering controls -> administrative controls(maintenance and design, restrict duration and level of exposure) -> PPE…. this is from most to least effective.
What is the objectives of BS EN60825-1:2014?
- to protect persons from laser radiation by indicating safe working levels and by introducing a system of classification
- lay down requirements - manufacturer and user - to establish
procedures for the supply of information - ensure adequate warning is given through the use of signs, labels and
instruction - reduce the possibility of injury by minimising access to laser radiation
via protective features and control measures
What are the classification classes determined by for lasers?
Accessible Emission Limit (AEL)
– Is the maximum level of laser radiation that can be
accessed from any product surface.
– This includes leakage radiation as well as main beams
from intended exit apertures.
– Classes take into account: laser wavelength, exposure
duration, viewing conditions
What are the main classes of this module and what do they do?
Class 1 – Practically no exposure to eyes or skin
Class 2 – Visible beams with safe exposure for eyes under certain
conditions
Class 3R – Higher output for specific use (uncommon in materials
processing). Not to view with binoculars or telescopes.
Class 3B – Still skin safe but not eye safe.
Class 4 – Unlimited → Practically all materials processing lasers, no maximum output and fire hazard.
The HIGHER the CLASSIFICATION = GREATER HARM potential
What is laser radiation damage depending on when its to your skin and eyes ? 5
- wavelength of radiation
- type of tissue exposed, eye or skin
- energy or power of the radiation
- size of the irradiated area
- exposure duration
How does intensity and divergence of the beam affect the laser?
A high intensity beam that can be focused, reflections can be hazardous.
Low divergence means the beam spreads out very little over large distances.
What is MPE? and what does it relate too?
Maximum Permissible Exposure. Level of laser radiation below which it is believed no harm will be done to the exposed individual. Applies to the eye and skin, depends on several factors like irradiance or radiant exposure.
What is Nominal Hazard Distance ?
NHD, At some distance, as the beam diverges, the irradiance of the laser beam will equal the MPE
* At greater distances the MPE will not be exceeded
* Laser is a hazard within this distance, and “safe” beyond it.
What are non-beam hazards?
- Hazards associated with a laser or laser product can present a greater
danger than the laser or radiation itself - Non-beam hazards are those other than optical radiation hazards
What are types of hazards defined by?
The way in which it is generated,
– Laser
– Beam Delivery
– Process
– Environment
– People
What are types of non beam hazards?
- Laser associated hazards arise directly from the laser or laser
installation - Beam delivery associated hazards can arise from the mode and
elements which make up the beam delivery system - Process associated hazards arise from the task or application that the
laser is performing - Environment & People. Different applications in different environments
by different people
What are electrical hazards?
- High voltage supplies supplies can be
lethal - Requires trained operators
- Electricity at Work Regulations apply
- High quality installation is critical
