Filter, Regulator, Lubricator (FRL) Assemblies Information

Filter, regulator, lubricator (FRL) assemblies are pre-pacFilter, regulator and lubricator (FRL) assemblykaged or modular assemblies of air filters, pressure regulators, lubricators, and gauges. Air leaving a compressor is hot, dirty, and wet and can cause damage to equipment and tools if it is not treated.

The filter cleans compressed air by trapping solid particles and separating liquids, such as oil and water, that are entrained in the compressed air. Filters are installed in the air line upstream of regulators, lubricators, and all pneumatically-powered tools and equipment. They remove contaminants from pneumatic systems, preventing damage to equipment and reducing production losses due to contaminant-related downtime. 

Pressure regulators control fluid pressure in compressed air systems. Regulators are also known as pressure reducing valves (PRVs). Pressure regulators maintain a constant output pressure regardless of input pressure variations and demands made on the system by downstream components.

Lubricators add controlled quantities of oil into the compressed air system to reduce the friction between moving components within air tools and other equipment that are powered by the system. Adding lubrication oil to the system also clears compressor oils that travel through the system in vapor form. To prevent build-up of oil within system components, mineral oils are added to the system to flush away the deposits.

Downstream equipment flow and pressure requirements determine the correct regulator and lubricator for the application. Manufacturers offer flow characteristics charts on their products to help chose the correct combination of regulators and lubricators.

Types of Filter, Regulator, Lubricator (FRL) Assemblies

There are several choices for regulator type.

  • General-purpose regulators are designed for typical industrial use; they generally operate only above atmospheric pressure.
  • High-pressure regulators are rated for inlet pressures higher than general purpose, typically over 1,000 psi.
  • Low-pressure regulators have special design characteristics for precise control of pressures typically below 15-20 psi.
  • Differential or bias regulators maintain a pressure differential between two locations in the system.
  • Pressure-reducing valves provide a sub-circuit with a supply of fluid at a pressure that is less than the pressure in the main circuit.


Performance specifications:

  • Regulating (adjustment) range - Dictates the limits of adjustment control
  • Maximum flow (gas or air) - Unnecessary to specify if primary application is liquid
  • Maximum pressure rating - Refers to the pressure rating for the valve or inlet pressure for the regulator
  • Filter minimum particle size rating - Applies to filter, regulator, and lubricator (FRL) assemblies. It is the smallest size particle that will be entrapped by the filter. This rating is an indication of the largest opening in the filter element.

Other important specifications include:

  • Regulator type 
  • Media
  • Adjustment control
  • Connectors or pipe size
  • Body material
  • Environmental parameters 


  • Integral pressure gauge
  • Pressure relief
  • Tamper-proof
  • Corrosive media


ADS AS3316--Filter Pack Assembly

BS ISO 6953-1--Pneumatic Fluid Power - Compressed Air Pressure Regulators and Filter Regulators

Image credit:



Already a GlobalSpec user? Log in.

This is embarrasing...

An error occurred while processing the form. Please try again in a few minutes.

Customize Your GlobalSpec Experience

Category: Filter, Regulator, Lubricator (FRL) Assemblies
Privacy Policy

This is embarrasing...

An error occurred while processing the form. Please try again in a few minutes.