API RP-500 Wall Mount Air Conditioners & Heat Pumps


  • Stand-Alone API-RP-500 Ventilation Systems & Emergency Ventilation Fans
    – Higher Air Flow Capacities for Special Needs
    – Separate Wall or Pad Mount Configurations

    – Separate or Shared Fresh Air Intake Stacks
    – Integrated or Independent Controls
  • Integrated or Stand-Alone Chemical Filtration Systems  to scrub Intake or Recirculated Air 
    – Provides a total environment control solution!

api rp-500 ventilation SYSTEMS

  • Meets & Exceeds all applicable API RP-500 Requirements
    – Maintains 6 Air Changes per Hour to permit Room Declassification
    – Provides Emergency Ventilation Mode to quickly reduce gas concentrations
  • Ultra-Quiet Backward Inclined Blower Wheels with Venturi Inlet Cones
    – Precision balanced and mated to ensure optimum performance 
  • Integrated Rheostats, Motors, Alarm Switches & G2 Safety Lockouts
    – All ventilation control devices, easily serviceable and within your unit!
  • Digital Air Velocity Indicator & Vent-Off-Auto Unit Control Switches
    – Provides feet per minute reading and full control of ventilation process
  • Emergency Ventilation Mode Activation & Dedicated Alarm Circuits
    – Permits remote activation of full speed ventilation in emergency conditions
    – Provides an insufficient air flow alarm with an adjustable delay
  • 3 Express Unit Air Flow Rates or Higher Custom Unit Air Flow Rates
    – Select a Size based on the Protected Space’s Total Volume in Cubic Feet
    – Maintains Air Exchanges through Dedicated Room Exhaust Vents

Associated options
& Installation enhancements

  • Flanged Air Intake Housings – to reach remote air sources
    – External Housings with Side or Top Intake Flange & Washable Screen Filters
  • Ground Level Air Intake Housings – to use surrounding air sources
    – External Housings with Rain Shields, Bug Screens & Washable Screen Filters
    – Available in  High Velocity Air Flow Configuration
  • Installation Enhancements
    – Dual or Shared Air Intake Stack Housings for Side-by-Side Units
    – Windload Certified Free Standing Rigid Pipe Air Intake Stacks
    – Adjustable Opposing Blade Damper Room Exhaust Vents

    – Spiral Pipe Air Intake Stacks, Guy Wire & Stanchion Kits

Scroll down or contact a Bebco Sales Associate to learn more…


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API RP-500 Ventilation Systems w/ Emergency Ventilation Mode

– A fully integrated solution for compliance to the American Petroleum Institute recommendations

As a two speed alternative to our NFPA 496 Pressurization Systems, Our API RP-500 Ventilation Systems feature a very similar onboard blower assembly!

As a distinct advantage, these integrated ventilation systems are protected against the surrounding atmosphere and stay cool, dry and clear throughout their service lifespan!

Please note Bebco is now seeking possible
ETL Certification to API RP-500 Recommended Practices. 
All Components are fully certified for the purposes they serve.

  • Meets & Exceeds all applicable API RP-500 Recommendations
    – Ensures continuous positive air changes and high velocity emergency ventilation
    – Offered in Unit Powered or 120 VAC Dedicated Emergency Circuit Powered Versions
  • Air Exchange Mode Operation
    – Provides Blower Speed Adjustment in Auto Mode to achieves required air exchange rate 
    –  Requires Bebco Room Exhaust Vents, featuring adjustable opposing blade dampers
  • Emergency Ventilation Mode Operation
    – Activated by Unit Control Switch or other Devices using the Emergency Activation Circuit
    – Quickly reduces room concentrations of flammable vapors to <25% LFL Levels
    –  Requires Bebco Room Exhaust Vents, featuring adjustable opposing blade dampers
  • Emergency Ventilation Mode & Dedicated Alarm Activation Circuit
    – Unit includes input terminals to demand full blower speed and quickly reduce LFL Levels
    – Intended for Room Gas or Oxygen Deficiency Detectors and Emergency Panic Switches
    – Dedicated Alarm Circuit indicates loss of air flow and features Activation Delay Timer
  • Integrated Digital Control Platform
    – Bebco seamlessly integrates all Unit, Blower and Alarm System functions and controls
  • Safety Lockouts – provided for Units with G2 Electrical Classification Ratings
    –  Override Mode prevents Unit operation.
    – Upon achieving safe conditions, Switching to Auto Mode enables Unit

Field test and proven components provide absolute reliability!

Click either Tab below to learn much more…

More Information

System Assembly Overview & Air Flow Ratings

Major Components

Bebco’s unique Two Speed Ventilation Systems for Express and Custom Series 1-6 Ton Wall Mount Air Conditioners and Heat Pumps are intended to salsify applicable API RP-500 Chapter 6 requirements.  

The Blower Assembly includes a venturi cone to draw air into a backward inclined aluminum blower wheel.

The wheel is driven by an air-cooled sealed bearing motor that is ETL Certified for Class I, Division 2, Group B service.

Motor speed is controlled by a Rheostat which is adjusted during start-up to achieve 6 air chages or the air flow rate required by the AHJ.

The Rheostate is mounted in an explosion-proof enclosure, along with the alarm circuit pressure switch and related components.

Bebco Ventilation Blowers meet the majority of most applications, but are available in larger sizes and stand-alone configurations with our Custom Series Units.

Please contact a Bebco Sales Associate
for your special applications!

Principals of Operation

Bebco Ventilation Systems are designed to supplement the Unit recirculating air evaporator blower and ensure adequate room air-changes, as determined by an AHJ, to satisfy API RP-500 Recommendations.

In addition, they are capable of providing up to a 3,100 SCFM  emergency ventilation air flow rate that can quickly reduce room concentrations of flammable vapors to <25% LFL Level.

Air Flow Ratings

Our Express Unit Ventilation Systems are offered in three air velocity ratings to satisfy API RP-500 recommendations for 6 or more air changes per hour, depending on the size of your room or building and the number of required air changes per hour:

V1:  100 – 300 CFM / Spaces up to 1,400 Cubic Feet

V2:  200 – 700 CFM / Spaces up to 3,200 Cubic Feet

V3:  360 – 1,300 CFM / Spaces up to 6,400 Cubic Feet

Size recommendations above based on achieving 6 Air Changes per Hour under normal operation and at least 12 Air Changes per Hour when the Emergency Ventilation Mode is activated

Cooling needs must be evaluated separately to determine Unit Size
Smaller Units may not accommodate our larger Ventilation Systems

Use our Calculator to determine your air flow requirements!

Need more air flow?

Please contact a Bebco Sales Associate…

Our Custom Units can feature larger blowers along with external, dual unit and stand-alone ventilation fans!

Control Features, Alarm Contacts and Override Provisions

Standard Controls                         

Bebco easily meets and exceeds API RP-500 Chapter 6 control system recommendations!

Bebco Ventilation Controls will include a Vent-Off-Auto Unit Control Switch and a Digital Air Flow Indicator installed adjacent to your Unit Controls.

Operation Sequence

  • Prior to start-up, the Unit Control Switch must be placed in the Vent Mode, unless the surrounding area and room interior are known to be non-hazardous.
  • Upon start-up, in the Vent Mode, the Unit shall be disabled and the Blower will operate at full speed. 
  • In the Off Mode, the Unit and Ventilation System shall be disabled. 
  • In the Auto Mode, the Unit shall be enabled and the Blower will maintain a preset air flow rate as required to achieve 6 or more air changes per hour, as required by an AHJ.

Flow Sensing Provisions

Bebco provides a flow sensor for your air intake that’s preinstalled or field connected to our Unit with two (2) 1/4″ tubes.

We also provide installation instructions and a full range of Air Intake and Stack sensor installation options!

Dedicate Alarm Contacts

Units with this System feature dedicated alarm contacts to supplement API RP-500 alarm recommendations.

These contacts are rated for 10 amps and are field adjustable to indicate insufficient air flow.

Emergency Override Circuits

All Units with this System will also feature an emergency ventilation mode activation circuit that can be triggered by room gas detectors or emergency panic switches in either local or remote locations. 

Completed the circuit by closing one or more contacts in parallel, will activate the ventilation mode.   

Do you have questions about
API RP-500 Requirements?

We offer free technical assistance and interpretation guidance,
and we also conduct online and in-person seminars.

Please see below to learn more!

Air Change Provisions

Satisfying Chapter 6 Air Change Recommendations

To satisfy air change recommendations under API RP-500 Chapter 6 and limit room pressure levels, Bebco recommends our Model REV Adjustable Opposing Blade Damper Room Exhaust Vents.  

These Vents are provided with optional materials and finishes and come with fully detailed instructions to set a continuous air change rate.  Please note our calculator provides guidance and you and your associates must determine the require air change rate.  Please learn more below and call us for more information.

We’ll help you understand all recommendations of API RP-500 Chapter 6!

We also offer Room Exhaust Vents along with Local and Remote Exchange Rate displays, if required by your AHJ.

Air Flow Monitoring – going beyond current recommendations

While not currently recommended by API, Bebco can furnish a variety of Air Flow Transmitters with our Custom Series Units to interface with our Smart Digital or Touch Screen Controls.  The Flow Sensors we provide may then be installed in the Air Intake Stack or at one or more points of dilution air flow discharge,  such as our Room Exhaust Vents.

Our Custom Units will also be provided with an emergency ventilation mode activation circuit and a 4-20 ma output signal.  These inputs and outputs allow you to display room air flow rates and quickly purge buildings remotely during emergency conditions.

This option is intended to satisfy advanced End User or AHJ Safety Standards.  By adding a flow transmitter, the monitoring recommendations of API RP-500 Chapter 6 will be exceeded.  Air changes can then be monitored, and insufficient room air exchange rates can trigger both local and remote alarm systems.

Our primary concern is for the safety and welfare of our Clients…

Bebco therefore provides a dedicated team of highly experience sales associates to assist you with understanding all recommendations of of API RP-500.  We conduct training seminars and webinars regularly, and will also be pleased to provide you with one-on-one support right now, as needed.
Simply click our chat button or give us a call to start learning!

Our relationship begins with ensuring your ability to meet applicable codes…

  • API RP-500 Interpretation & Application Assistance
    – Line level review to compare their recommendations  against your specs
  • Critical Building Design Consideration Audits
    – Review of walls, floors, ceilings, doors, windows and vapor barriers
  • Critical Room Equipment Suitability Audits
    – Review of all installed and future equipment ratings and characteristics
  • Determining NFPA 497 Electrical Classification Ratings
    – Understanding classifications of your space and surrounding area
  • Required Door Markings & Air Velocity Calculations
    – Safety review covering markings, door areas and limited releases
  • Selecting Bebco Unit Ratings & Optional Features
    – Guidance and details on the products that best meet your needs

Need a copy of API RP-500?

Please visit the API Bookstore now!

API Book store

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Associated Options & Installation Enhancements

– We provide a turn-key solution for your entire application

Ventilation System Air Intakes

Bebco offers a complete range of air intake housings that permit you to source ventilation air from ground level or remote sources.

Hi Volume Ground Level Air Intake
This housing is suitable if the surrounding area has been rated as Unclassified by the AHJ, while the interior of your room or building is deemed by the AHJ to be a Hazardous Location. 

Side & Top Flanged  Air Intakes
These housing facilitate easy connection to any form of duct, including flexible duct kits, spiral pipe stacks and free-standing rigid pipe stacks.   And yes, you guessed it – we offer all that too!

Dual or Shared Air Intake Stack Housings

Bebco offers Dual Air Intake Housings that permit you to draw air into two side-by-side Units from a common source.  Material, finish and  mounting provisions are optional, and these housings can also contain one or more filters in succession, to filter and pre-treat inlet air.

Adjustable Opposing Blade Damper Room Exhaust Vents
These Exhaust Vents discharge room air to the surrounding area.  They feature opposing blade dampers to regulate air changes for Ventilation Systems that must comply with Chapter 6 of  API RP-500.  This Vent is attached externally, and blades can be adjusted outside the building.  Optional grilles are also available at time of order to cover the interior wall cutout. 

Spiral and Free Standing Rigid Pipe Stacks
Bebco offers a comprehensive solution for all remote air intake needs.  From Flexible Duct Kits to Spiral Pipe Kits with Guy Wires or Stanchions and our Free-Standing Rigid Pipe Stacks, we have it all!  And best of all, we also provide essential engineering services, highly detailed installation diagrams and site-specific windload certifications!


Please contact a Bebco Sales Associate now to learn more about our Integrated API RP-500 Ventilation Systems or reserve time with an Application Specialist to discuss your project!