Lecture 15 (Confined Spaces) Flashcards
Confined Space
An enclosed or partially enclosed area that is big enough for a worker to enter.
Three Elements
limited openings for entry and exit
Not designed for continuous worker occupancy
Large enough so employee can enter and work
Examples of Confined Spaces
Bins, Bunkers
Tanks, Trenches, Tunnels
Boiler, Furnace
Portal Size
Restricted - portal ≤ 24” in least dimension
Unrestricted - portal ≥ 24” in least dimension
Horizontal Space Access
Portal located on side of permit space
use of retrieval lines could be difficult
Vertical Space Access
Portal located on top of permit space
Rescuers must climb up or down to enter space
Natural Ventillation
Deadly gases can be trapped inside
Organic materials can decompose
May not be enough oxygen due to presence of other gases
Dangerous Combinations
Worsened conditions due to work activities:
Welding and cutting, use of bonding agents
Use of gas-powered equipment
Confined Space Hazards
Safety Hazards
Atmospheric Hazards
Unsafe Actions lack of education and training, lack of enforcement
People Needed
Entrant: Read, date and sign report
Person outside the entrance (standby)
Back-up: Near Vicinity
Employer’s Responsibilties
Instruct and train workers
Provide PPE and emergency equipment
Appoint a competent tester
Ensure that the worker has read, dated and signed the report
Competent Person
Knowledgeable
Be trained in the procedures
Ensure constant communication
Have a standard-level first aid and CPR
Employee’s Responsibilities
Competent person follows procedures
Use PPE and emergency equipment
Read and sign the report of the competent tester
Written Program
Identify Confined Spaces Recognize Hazards Testing and Controls Emergency Procedures and Rescue Responsible Parties Standby Procedures Training Requirements Permit Requirements Pre-entry Requirements and Checks
Permit Entry Systems
Written permit signed by entry supervisor
Posted at entry to confined space
Permit Entry Requirements
Date, location, and name of confined space.
Purpose of entry and known hazards.
Duration of entry permit time.
Authorized entrants, attendants, supervisors. (and More)
Testing Protocol
Before employee enters space, internal atmosphere shall be tested for: Evaluation testing Verification testing Duration of testing Testing stratified atmosphere
Oxygen
If Less than 19.5% Use appropriate RPE
If more than 23%
No flammable, combustible or reactive material
19.5 % Oxygen Deficiency
Minimum acceptable oxygen level.
4-6% Oxygen Deficiency
Coma in 40 seconds. Death
8-10% Oxygen Deficiency
Mental failure. Fainting. Nausea Unconsciousness. Vomiting.
Oxygen Enriched Atmoshperes
Oxygen level above 21%.
Causes flammable and combustible materials to burn violently when ignited.
Never use pure oxygen to ventilate.
Flammable Atmosphere
2 Critical Factors:
Oxygen content in the air.
Presence of a flammable gas, or vapour
Toxic Atmospheres
Product stored in a confined space:
Gases released when cleaning
Work performed in a confined space:
Painting, scraping, sanding, degreasing
Hydrogen Sulfide
Comes from decomposition of materials. Human waste.
Rotten egg odor at low concentrations.
Possibly no warning at high concentrations.
Carbon Monxide
Odorless, Colorless Gas
Combustion By-Product.
Quickly collapse at high concentrations.
Temperature Extremes
Extremely hot or cold temperatures
Extremely cold liquids
Work processes inside the confined space can increase temperature extremes
Engulfment Hazards
Loose, granular materials stored in bins and hoppers - grain, sand, coal, etc
Water or sewage flow
Other Hazards
Noise
Slick / Wet Surfaces
Falling Objects
Insects or animals
Ventilation
First option to correct problems
Air intake in a safe location to draw fresh air only
Must be aware of hazards you are trying to correct in the confined space
Respirators
Air-Purifying Respirators
– Filter dangerous substances from the air
Air-Supplying Respirators
– Deliver a safe supply of breathing air from a tank
Isolation
Locking and tagging out electrical sources
Blanking sewer and water flow
Locking and tagging out shutoff valves
