Pressure Vessel
A Pressure Vessel is a container or equipment designed to hold gases or liquids at a pressure higher than atmospheric pressure. It is used in various industries, including manufacturing, chemical processing, and power plants.
Definition as per Gujarat Factory Rules 1963 - Rule 61
As per the Gujarat Factory Rules and relevant Indian Standards (e.g., IS 2825 – Code for Unfired Pressure Vessels), a pressure vessel is:
"Any vessel or apparatus (other than a boiler) which contains gas, steam, or liquid at a pressure greater than atmospheric pressure."
Key Features of Pressure Vessels
- Design Pressure: Operates at a pressure above atmospheric pressure.
- Material Strength: Built with materials that withstand high pressure (e.g., steel, alloys).
- Safety Devices: Equipped with safety valves, pressure gauges, and rupture discs.
- Testing & Certification: Requires periodic inspection and hydrostatic testing.
Examples of Pressure Vessels
- Air receivers
- LPG storage tanks
- Heat exchangers
- Chemical reactors
Basic Requirements for Pressure Vessels
Provisions Under Gujarat Factory Rules, 1963 (Rule 61 - Pressure Vessel & Plant)
(A) Design & Construction
- Must be designed and constructed as per Indian Standards (IS 2825: Code for Unfired Pressure Vessels).
- Withstand the maximum working pressure and temperature.
(B) Installation & Operation
- Installed securely to avoid risk due to pressure fluctuations.
- Operated within the safe working pressure (SWP).
- Equipped with safety devices like pressure gauges, relief valves, and automatic cut-off systems.
(C) Testing & Inspection
- Periodic inspection by a competent person.
- Hydrostatic or non-destructive testing (NDT) at regular intervals.
- A register of pressure vessels must be maintained.
(D) Safety Measures
- Pressure vessels must have conspicuous marking of safe working pressure (SWP), test date, and manufacturer's details.
- Operators must be trained and authorized.
(E) Repair & Maintenance
- Modifications or repairs should be done under expert supervision.
- Weak or corroded vessels must be repaired or replaced immediately.
Provisions Under The Factories Act, 1948 (Section 31 - Pressure Plant)
- Approval & Certification: No pressure vessel should be used without proper inspection and approval.
- Safety Measures: Safeguards to prevent excessive pressure buildup, adequate strength, and safety valves.
- Testing & Maintenance: Periodic testing must be conducted, and records kept for inspection.
- Competent Person Certification: Only certified personnel can inspect and certify pressure vessels.
Inspection & Testing Requirements as per Gujarat Factory Rules, 1963
- External Examination: Every 6 months by a Competent Person.
- Internal Examination: Every 12 months (hydrostatic test every 2 years if internal examination is not possible).
- Hydrostatic Test: Every 4 years (exceptions for thin-walled vessels).
Summary of Additional Requirements (Gujarat Factory Rules, 1963)
- If external examination every 6 months is impractical, it must be done at least once in 2 years.
- If hydrostatic testing is not feasible, a non-destructive test (NDT) like ultrasonic thickness testing must be done.
- Test pressure should be 1.25 × Design Pressure or 1.5 × MPWP (whichever is less).
- Thin-walled vessels have specific lifespan and testing requirements.
- All test reports must be recorded and signed in Form No. 11, with copies sent to the Inspector if safety conditions are required.
