In the workplace, safety in becoming a crucial part, and not only that it becomes a social and legal obligation to provide a safe and healthy working environment to all employees working at the workplace. To avoid hazards and danger, permit to work system needs to follow in industries. There are different types of PTW which we had discussed earlier among with OSHA confined space entry permit was one of them.
In the previous post, we had discussed the Safety Hierarchy Of Controls in which we had mentioned Administration control, permit to works falls in this control hence we define permit to work as an Administration tool.
In industries, there are lots of equipment that are used in the manufacturing of products, and over time, as the equipment is used, maintenance needs to be done of that equipment and machine. For maintenance purposes or cleaning, sometimes it is required to make man enter into the equipment or the vessel to perform such task. In such a situation, certain steps need to be followed to avoid the dangers of confined space entry.
Today, in this guide, we will learn what is confined space entry permit and what is the confined space entry procedure. We had also included a detailed example which is used in industry which will gives you practical knowledge about the osha confined space permit procedure.
What is confined space entry permit?
A confined space entry also refer as vessel entry and OSHA defined the term permit-required confined space. Industries and some workplace have equipment and areas fall under Confined space which is not meant work person but has a provision for personnel entry to perform a certain task. They include any vessel, tank, container, pit, or any other similar space which has a very limited opening which is not suitable to work for a longer time and this eclosed system gives rise to the occurrence of an accident.
What are the hazards associated with confined spaces?
Numbers of hazards are associated with the vessel enty permit and one has to consider all these possibility of hazards under consideration while issuing confined space entry permit. Associated hazard with vessel entry permits are listed below.
- Toxic Atmosphere
- Oxygen Deficiency
- Oxygen Enrichment
- Flammable or Explosive Atmospheres
- Flowing of material (liquid or solid)
Tank, vessel or any equipment used in the manufacturing of product contains to store or react chemical and chemical can be toxic in nature. When vessel entry needs to be taken in such equipment, there is a danger of toxic atmosphere that can cause to the person when the person takes entry in the equipment. It is important to perform proper cleaning of the equipment and air monitoring need to be done to check if the tanks is gas-free. Proper Degassing needs to be done if poisonous and toxic gases used to store in the equipment.
Confined space has a very limited opening and is not meant for man to work inside continuously. Human beings normally breathe air that is 20.9 percent oxygen by volume under normal atmospheric pressure. When the percentage of oxygen decreases by 1 to 2 percent also, the person feels difficult to breathe. The condition of a decrease in oxygen percentage for humans to breathe is called oxygen deficiency. Prior to entry into the confined space, air monitoring is performed to check whether the oxygen content in the vessel is sufficient or not. The leading causes of fatality in vessel entry is oxygen deficiency. It is always important to have a maximum opening in the vessel to have enough oxygen level in the vessel
Oxygen enrichment means the presence of excess oxygen inside a confined space. Oxygen is required to complete the fire triangle. If the oxygen is present in more volume, the possibility of fire and explosion increases, and fire in such an atmosphere is more intense. This is mostly happening due to leakage from the oxygen cylinder
Flammable or Explosive Atmospheres
The presence of flammable or explosive chemicals or atmosphere can lead to a danger of fire and explosion. As the vessel had limited air movement possibility of fire and explosion in the vessel can be increased due to the presence of the flammable atmosphere.
Flowing of material (liquid, gas or solid)
Blind must be applied to all inlet and outlet pipelines connected to the equipment to avoid any inlet of material in the equipment. To be on safer side, all the connected lines to be disconnected. While man working inside the vessel, flowing of material solid or liquid causing suffocation, burns to body or drowning and any other injuries. Inlet of gases can create an asphyxiation atmosphere and can lead to fatality.
Vessel entry permit checklist
Discussion with the department : Area supervisor and operator along with the maintenance department need to be aware of the work.
Barricade : Signaling and barricading is important to make people aware and avoid error in operation.
Oxygen content levels : Oxygen level should be between 19.5 to 23.3% by volume
Isolation : Electrical isolation to be done if any equipment is present inside the vessel.
Proper lightning : Only 24 volt bulb is to be use in vessel entry.
Air Monitoring and Testing
Air monitoring and testing is an important step in permit-required confined space and it is to be done by ESH officer and reading of the air monetering is to be mentioned in work permit along with the signature of safety officer for approval from safety department. Modern testing equipment’s perform test in the below sequence and it wont proceed to other test until first is clear. If the testing equipment is manual, the one has to wait untill the test result is stable and then proceed to other test.
- Test for oxygen
- Test for combustible gases and vapors
- Test for toxic gases and vapors
Confined Space Entry Procedures
Now we had learned what is OSHA Confined Space Entry permit system and what are the hazards associated with it. Now let us proceed with the procedure with the procedure of teh safety permit.
Who issues a confined space permit?
In industry, when vessel entry is to be taken in any tank or vessel, production department supervisor discussed with the maintenace department person about the work and task that need to be done for which vessel entry to be taken. After discussion, production department person identifies all the hazer
- Performing Risk Assessment
- Electrical isolation of equipment or component associated with it
- Cooling the equipment
- Barricading the area
- Equipment Cleaning and send a sample for checking of presence of any chemical
- Issuing of a safety Entry Permit which includes purpose, place, and duration of the task.
- Checking by the maintenance department and EHS officer
- Atmosphere Testing & Monitoring (EHS officer)
- Allow the man to enter and work
- Closing of work permit
These were the confined space work procedure and one has to follow all these steps mandatory to avoid any accident or incident in industry.
Example of Confined space entry in a reactor
Now, we had all the required information realted to confined space entry but knowledge is incomplete without practical knowledge. Let us take and example where we had to take vessel entry into a reactor for mainentance of the stirrer. Below are the steps that we need to follow in industry.
- Discussion with the maintenance department for the maintenance of the stirrer.
- Proper cleaning to be performed also known as product change over cleaning by vaporizing solvent in which the previous product is soluble followed by reflux of water and sample of rinsed water to sent to check for checking of decontamination which makes us assure that reactor is free from any chemical.
- The reactor is to be cooled to 25 °C by applying utility and the reactor jacket also needs to be empty
- Now electrical isolation of stirrer to be performed to avoid staring of stirrer while man is working and also emergency switch to be activated.
- All the connected lines to be either disconnected or blind to be applied and to be done the same with the utility lines of the reactor. Vent lines is to be kept open for proper ventilation.
- Confined space permit to be an issue and get it approved by the maintenance department and then EHS office requests for inspection
- Air monitoring along with checkpoints to be check and oxygen level reading to be shown to the person who is going to enter into the reactor
- 24 Volt bulb is to be provided by the electrical department if needed.
- After getting approval by the EHS department and the permit getting signed by the stand-by person, the trained person is allowed to perform the maintenance task wearing the required PPEs.
These are the steps that producition, maintenance and EHS department has follow to get task done in OSHA Confined Space Entry permit.
FAQ permit-required confined space
What is the safe oxygen level for confined space?
According to OSHA, safe oxygen limit in vessel entry is between 19.5 to 23.3 % by volume as below 19.5 % creates oxygen deficiency and above 23.3% creates oxygen enrichment.
How to check oxygen level in confined space?
Various devices are available in the market which gives you the digital reading about the oxygen level in the confined space.
What are osha confined space air monitoring requirements
According to OSHA’s confined space standard 1910.146. It is mandatory to test internal atmosphere of the confined space and to be in the given order
- First – Oxygen content,
- Second – Flammable gases and vapors and
- Third – Potential toxic air contaminants.
This was the detailed information regarding OSHA Confined space entry permit and everything you need to know about confined space entry. If you have any problem regarding confined space entry or hazards associated with the Confined Space Entry procedure then feel free to use the comment section and start the discussion with us. We had posted various articles related to chemical engineering and industrial safety like what are the 4 stages of a fire? and Duties Of Safety Officer Under Gujarat Factory Rules so do read those and stay updated in that domain as well.