Industrial Workplace Safety and Ventilation

Confined Space Requirements

• Flammable gases and vapors (LEL) below 5%
• Potential toxic air contaminants: CO and NH3 maximum allowable concentration is 25 PPM
• Wet bulb globe temperature ≤ 35°C or Ambient Temp ≤ 46 °C as maximum

Ventilation Requirements for Confined Space

• Ventilation plan shall be prepared and approved as per IMRS 13-02-01-23
• Positioning of mechanical aspirators, drawing of fresh air, routing of exhaust air
• Air conditioners can be installed as an alternate of ventilation wherever it is convenient
• A positive means of ventilating confined space shall be established and kept operated the entire time while work is in progress

Rescue Plan Preparation and Requirements for Confined Space Entry

• Rescue plan is mandatory for all Confined Space entry types
• Rescue Plan shall consider the hazards outcome of the JSA, location of the work, number of workers, duration and period of work, and resources needed for the rescue

Definitions

• Wet-bulb globe temperature (WBGT): estimates the effect of temperature, humidity, wind speed, and radiation on humans
• Explosive substance: a chemical substance that causes a sudden release of pressure, gas, and heat when subjected to shock, pressure, high temperature, or chemical reaction
• Rescue plan: a plan used to rescue persons from the Confined Space regardless of confined Space category
• Lifeline/Retrieval line: a line used for preserving or saving life in a dangerous or potentially dangerous situation
• Venting: allowing gases or vapors to be released to the atmosphere or flare or a recovery system during depressurization or purging
• Ventilation: ventilating a vessel or area by using an air-moving device to draw fresh air through the vessel or area
• Breathing Apparatus: line-air supplied via manually operated pump or cylinders of compressed air, self-contained apparatus carried by the wearer or a recycled air system

Confined Space Hazard Identification and Preparation

• Confined space hazard identification shall be recognized by posting sign boards stating the confined space condition
• Preparation includes:
  • Free of dangerous chemical substances/liquid as far as practically possible for “A” category and mandatory for “B” category
  • Energy isolation in terms of electrical isolation, positive isolation, and radiation source removal
  • No process material remains
  • Sewer openings in immediate area shall be covered
  • Air shall be tested, and ventilation shall be provided
  • Communication systems shall be available

Ventilation Requirements and Gas Testing for Confined Space

• Oxygen content between 19.5% to 22.0%
• Canisters, cartridge, and other forms of filter mask do not constitute Breathing apparatus

Definitions

• Lower Explosion Limit (LEL): the minimum concentration of vapor in air below which propagation of flame will not occur in the presence of an ignition source
• Threshold Limit Value (TLV): toxic gas concentration above which it is not safe to work extended periods
• Upper Explosive Limit (UEL): the maximum concentration of a flammable/combustible gas, vapor, mist, or dust in air that will support combustion when an ignition source is present
• Gas Tester: a person who has undergone training on the use of gas detecting equipment and is authorized to conduct gas tests
• Oxygen Deficient Atmosphere: an atmosphere containing less than 19.5% by volume oxygen at sea level
• Oxygen Enriched Atmosphere: an atmosphere containing more than 22.5% oxygen by volume