Equipment and Piping

Equipment Piping Process Safety Management

Process safety programs require that all equipment be designed, operated and maintained to the highest standards. In practical terms this requirement means that if the equipment and piping always retains its integrity, i.e., if it does not leak, then then highly hazardous materials will not be released.

Process safety programs often place the management of equipment and piping into the overall category of Asset Management or Mechanical Integrity.

Equipment and Piping Scope

The following is a list of the typical equipment covered by a process safety mechanical integrity program.

  • Pressure Vessels and Columns
  • Storage Tanks
  • Pumps
  • Compressors
  • Turbines
  • Heat Exchangers
  • Air-Cooled Exchangers
  • Cooling Towers
  • Fired Heaters
  • Flares / Blowdown
  • Boilers
  • Internal Combustion Engines
  • Electrical Equipment
  • Buildings
The following is a list of the typical piping and valves that are covered by a process safety mechanical integrity program.
  • Pipe (specifications and sizing)
  • Materials
  • Equipment Piping
  • Fittings
  • Flanges
  • Gaskets
  • Blinds
  • Flame Arrestors
  • Vortex Breakers
  • Hoses
  • Block Valves
  • Globe / Control Valves
  • Rotary Valves
  • Check (Non-Return) Valves
  • Flangeless Valves
  • Valve Seat Materials
  • Valve Position
  • Steam Traps
  • Pressure Safety Relief Valves
  • Thermal Relief Valves
  • Rupture Disks

Regulations, Codes and Standards

There are many regulations, codes and standards to do with the mechanical integrity element of process safety management programs. Some of the key standards-setting bodies are:

  • American Chemistry Council / Responsible Care®
  • American National Standards Institute (ANSI)
  • American Petroleum Institute (API)
  • American Society of Mechanical Engineers (ASME)
  • International Organization for Standardization (ISO)
  • National Fire Protection Association (NFPA)

In the United States important process safety management regulations are published by:

  • The Environmental Protection Agency (EPA)
  • The Occupational Safety & Health Administration (OSHA) 
  • The Bureau of Safety and Environmental Enforcement (BSEE)

Additional Information

Further information and guidance to do with process safety mechanical integrity is provided in the following publications:

Pig Launching and Retrieving

Pipeline pigs (also known as 'scrapers' and 'tools') are widely used to clean piping, to provide a buffer between two liquids and to inspect the integrity of the line (using 'smart pigs'). Whatever the reason for pigging a line the pig has to be launched and then retrieved. This article provides an overview of launching and catching procedures.

Equipment Isolation Methods

Isolation Methods

Positive isolation methods are those which remain effective even if there is equipment failure or operator error. These techniques apply not only to vessels, piping and tanks but also to pneumatic and hydraulic equipment.

The sketch shows some of the various isolation techniques that can be used to protect workers in the process industries. The process containing toxic or flammable chemicals under pressure is on the left; the open system, where the workers are present, is on the right. The order is from the least to the most secure.

Siting and Layout of Process Facilities

Siting

Siting and Layout: The words ‘siting’ and ‘layout’ are often used interchangeably, but, strictly speaking, they have different meanings. Siting is concerned with the location of a facility. For example, if a company is planning on building a new chemical plant its management may consider the relative merits of sites in Texas, Mexico or China. Layout, on the other hand, is to do with the locations of equipment, piping and buildings at the selected site and how they connect with one another.

Plugged Process Piping

Plugged Process Piping. Process lines, piping and valves frequently become plugged. Various techniques for avoiding the formation of pluggage and for removing pluggages safely are discussed.

If line pluggage is a recurring problem it is best to try and identify ways in which the problem can be prevented from occurring. If that solution is not possible then valves, drains, tees and connections should be designed so that it is possible to remove the pluggage safely and with minimum time and expense.

Storage Tanks in the Process and Energy Industries

Storage tanks are widely used in the process industries to store liquids that are below their boiling point at atmospheric temperature (some tanks may be insulated and they may have heating or cooling coils to maintain the temperature of the liquid that they are storing). Typically, tanks are either open to the atmosphere or to a system such as a flare or vent header that is at atmospheric pressure (this does not apply to floating roof tanks). Unlike pressure vessels, storage tanks cannot handle either high pressure or vacuum conditions.

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