Safety in confined space

Editor's Notes

• #2: Welcome to the training on Safety in Confined Space by the Apprentice. We appreciate that you have taken this course from our Library. Please provide us with feedback at the end of the program that helps us in continuous improvement.
• #4: Hello, I am Ryan and I will take you through this session on Confined Space. A confined space found in the workplace may have a combination of these three characteristics: Limited openings for entry and exit ; Unfavorable natural ventilation; Not designed for continuous worker occupancy; These can complicate working in and around these spaces as well as rescue operations during emergencies. If a survey of your working area identifies one or more work spaces with the characteristics listed above. Let’s understand these in a bit more detail.
• #5: So, what is meant by Limited opening for entry and exit, let’s see … Confined space openings are limited primarily by size or location. Openings are usually small in size , perhaps as small as 18 inches in diameter, and are difficult to move through easily. Small openings may make it very difficult to get needed equipment in or out of the spaces, especially protective equipment such as respirators needed for entry into spaces with hazardous atmospheres, or life – saving equipment when rescue is needed. However , in some cases openings may be very large , for example open-topped spaces may require the use of ladders, hoists, or other devices, and escape from such areas may be very difficult in emergency situations.
• #6: Next, let’s understand what is meant by Unfavorable natural ventilation. Because air may not move in and out of confined spaces freely due to the design, the atmosphere inside a confined space can be very different from the atmosphere outside. Deadly gases may be trapped inside, particularly if the space is used to store or process chemicals or organic substances which may decompose. There may not be enough oxygen inside the confined space to support life, or the air could be so oxygen-rich that it is likely to increase the chance of fire or explosion if a source of ignition is present
• #7: What do we mean by this - Not designed for continuous worker occupancy. It means that these places are are not designed for workers to enter and work in them on a routine basis. They are designed to store a product, enclose materials and processes, or transport products or substances. Therefore, occasional worker entry for inspection, maintenance, repair, clean up, or similar tasks is often difficult and dangerous due to chemical or physical hazards within the space.
• #8: So, what are the hazards of entering and working in Confined Spaces?
• #9: As mentioned, the atmosphere in a confined space may be extremely hazardous because of the lack of natural air movement. This characteristic of confined spaces can result in Oxygen-deficient atmospheres, Flammable atmospheres, and / or Toxic atmospheres. Let’s delve into these issues a little more.
• #10: An oxygen-deficient atmosphere has less than 19.5% available oxygen (O2) . Any atmosphere with less than 19.5% oxygen should not be entered without an approved self-contained breathing apparatus (SCBA). The oxygen level in a confined space can decrease because of work being done, such as welding,cutting, or brazing; or,it can be decreased by certain chemical reactions (rusting) or through bacterial action (fermentation). The oxygen level is also decreased if oxygen is displaced by another gas, such as carbon dioxide or nitrogen. Total displacement of oxygen by another gas, such as carbon dioxide, will result in unconsciousness, followed by death.
• #11: Two things make an atmosphere flammable: 1. the oxygen in air; and 2. a flammable gas, vapor,or dust in the proper mixture. Different gases have different flammable ranges. If a source of ignition (e.g., a sparkling or electrical tool) is introduced into a space containing a flammable atmosphere , an explosion will result. An oxygen-enriched atmosphere (above 21%) will cause flammable materials , such as clothing and hair, to burn violently when ignited. Therefore, never use pure oxygen to ventilate a confined space. Ventilate with normal air
• #12: What are TOXIC ATMOSPHERES ? Most substances (liquids, vapors, gases, mists, solid materials and dusts) should be considered hazardous in a confined space. Toxic substances can come from the following: The product stored in the space: The product can be absorbed into the walls and give off toxic gases when removed or when cleaning out the residue of a stored product, toxic gases can be given off. Example: Removal of sludge from a tank decomposed material can give off deadly hydrogen sulfide gas.
• #13: Let’s now see what actions should be taken before entering a confined space.
• #14: First thing to do is to test the atmosphere. It is important to understand that some gases or vapors are heavier than air and will settle to the bottom of a confined space. Also, some gases are lighter than air and will be found around the top of the confined space. Therefore, it is necessary to test all areas (top, middle, bottom) of a confined space with properly calibrated testing instruments to determine what gases are present. If testing reveals oxygen-deficiency, or the presence of toxic gases or vapors, the space must be ventilated and re-tested before workers enter. If ventilation is not possible and entry is necessary (for emergency rescue , for example) , workers must have appropriate respiratory protection. NEVER TRUST YOUR SENSES TO DETERMINE IF THE AIR IN A CONFINED SPACE IS SAFE YOU CAN NOT SEE OR SMELL MANY TOXIC GASES AND VAPORS NOR CAN YOU DETERMINE THE LEVEL OF OXYGEN PRESENT
• #15: Ventilation by a blower or fan may be necessary to remove harmful gases and vapors from a confined space. There are several methods for ventilating a confined space. The method and equipment chosen are dependent upon the size of the confined space openings, the gases to be exhausted (e.g., are they flammable?), and the sources of makeup air.   Under certain conditions where flammable gases or vapors have displaced the oxygen level, but are too rich to burn, forced air ventilation may dilute them until they are within the explosive range. Also , if inert gases(e.g. carbon dioxide , nitrogen , argon) are used in the confined space, the space should be well ventilated and re-tested before a worker may enter.   A common method of ventilation requires a large hose, one end attached to a fan and the other lowered in to a manhole or opening. For example, a manhole would have the ventilating hose run to the bottom to blow out all harmful gases and vapors. The air intake should be placed in an area that will draw in fresh air only. Ventilation should be continuous where possible , because in many confined spaces the hazardous atmosphere will form again when the flow of air is stopped
• #16: Isolation of a confined space is a process where the space is removed from service by: Locking out Electrical sources , preferably at disconnect switches remote from the equipment.     Blanking and bleeding Pneumatic and hydraulic lines     Disconnecting Belt and chain drives , and mechanical linkages on shaft – driven equipment where possible and     Securing Mechanical moving parts within confined spaces with latches , chains, blocks
• #17: Respirators are devices that can allow workers to safely breathe without inhaling toxic gases or particles. Two basic types are air-purifying, which filter dangerous substances from the air, and air-supplying, which deliver a supply of safe breathing air from a tank or an uncontaminated area nearby. ONLY AIR- SUPPLYING RESPIRATORS SHOULD BE USED IN CONFINED SPACES WHERE THERE IS NOT ENOUGH OXYGEN.   Selecting the proper respirator for the job, the hazard, and the person is very important , as is thorough training in the use and limitations of respirators.
• #18: A standby person should be assigned to remain on the outside of the confined space and be in constant contact (visual or speech) with the workers inside. The standby person should not have any other duties but to serve as standby and know who should be notified in case of emergency. Standby personnel should not enter a confined space until help arrives, and then only with proper protective equipment , life lines , and respirators. Over 50% of the workers who die in confined spaces are attempting to rescue other workers. Rescuers must be trained in and follow established emergency procedures and use appropriate equipment and techniques (lifelines , respiratory protection, standby persons,etc.). Steps for safe rescue should be included in all confined space entry procedures. Rescue should be well planned and drills should be frequently conducted on emergency procedures. Unplanned rescue, such as when someone instinctively rushes in to help a downed co-worker, can easily result in a double fatality, or even multiple fatalities if there are more than one would – be rescuers.     REMEMBER : AN UNPLANNED RESCUE WILL PROBABLY BE YOUR LAST.  
• #19: GENERAL / PHYSICAL HAZARDS TEMPERATURE EXTREMES: Extremely hot or cold temperatures can present problems for workers. For example , if the space has been steamed , it should be allowed to cool before any entry is made.     ENGULFMENT HAZARDS:   Lose , granular material stored in bins and hoppers , such as grain , sand, coal or similar material , can engulf and suffocate a worker. The loose material can crust or bridge over in a bin and break loose under the weight of a worker.
• #20: NOISE: Noise within a confined space can be amplified because of the design and acoustic properties of the space. Excessive noise can not only damage hearing, but can also affect communication, such as causing a shouted warning to go unheard.   SLICK/WET SURFACES:   Slips and falls can occur on a wet surface causing injury or death to workers. Also , a wet surface will increase the likelihood for and effect of electric shock in areas where electrical circuits, equipment , and tools are used.   FALLING OBJECTS :   Workers in confined spaces should be mindful of the possibility of falling objects, particularly in spaces which have topside openings for entry , and where work is being done above the worker.
• #23: Here is the check-list for monitoring .
• #24: CLEANING checks Has the space been cleaned before entry is made? Was the space steamed? If so , was it allowed to cool?
• #25: VENTILATION Has the space been ventilated before entry?   Will ventilation be continued during entry?   Is the air intake for the ventilation system located in an area that is free of combustible dusts and vapors and toxic substances?   If atmosphere was found unacceptable and then ventilated, was it re-tested before entry?
• #26: ISOLATION Has the space been isolated from other systems? Has electrical equipment been locked out?   Have disconnects been used where possible?   Has mechanical equipment been blocked , chocked, and disengaged where necessary?   Have lines under pressure been blanked and bled ?
• #27: Here is a checklist for CLOTHING / EQUIPMENT , please go thru it.  
• #28: Here is a checklist for RESPIRATORY PROTECTION
• #29: Please read the checklist for TRAINING
• #30: Here is a checklist with regard to STANDBY/ RESCUE
• #31: Work PERMIT The permit is an authorization in writing that states that the space has been tested by a qualified person, that the space is safe for entry ; what precautions, equipment , etc. are required; and what work is to be done. Check - Has a confined space entry permit been issued? Does the permit include a list of emergency telephone numbers? In fact the checks mentioned in previous slides can be part of Work-Permit Issuance. And, work in confined space must not begin without a authorized person has issued a work-permit.
• #32: Let’s summarize what we have learnt. We have learnt What is a confined space? Hazards of entering and working in Confined Spaces Actions to taken / Preparation before entering a confined space Checklist prior to commencing work in a confined space. Next is small quiz for you …