Environmental Chambers and Space Simulation Systems

AF Altitude, Temperature/Altitude, and Temperature/Humidity/Altitude Chambers Literature Download

AF Altitude, Temperature/Altitude, and Temperature/Humidity/Altitude Chambers Literature Download

Temperature/Humidity/Altitude Chambers

Bemco AF Chamber with Door Open

Bemco AFW Temperature, Humidity, and Altitude chambers add humidity capability to the already outstanding features of the Bemco AF series of Temperature/Altitude chambers.

With a standard desiccant drier and a direct humidity sensor you can reliably test your product in both high and low humidity without having to move to another chamber. Humidity operation is always at ambient pressure.

It’s no wonder that we are the number one supplier of Altitude, Temperature/Altitude and Temperature/Humidity/Altitude chambers in America. What is our formula for success? The key word is quality.


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AFW Series chambers include a 304 Series stainless steel welded inner pressure liner with high temperature fiberglass insulation. No asbestos is used in chamber construction. The chamber liner is reinforced in accordance with Section VIII (Unfired Pressure Vessels) of the ASME Code.

The outer case is fabricated from cold rolled steel finished in Bemco Blue. Chamber doors feature Bemco’s dual gasket construction with a replaceable inner “O” ring. One or more, over-center Bemco cam-type latches, seal the door.

AFW Series chambers include a sloped roof insert to minimize potential water dripping on test objects in accordance with MIL-STD-810 and MIL-STD-202. This feature reduces overall height in the workspace by 1-1/2 inches. The AFW chambers also include a trapped drain line to remove condensed water from the workspace and a door drip through to catch condensed water.

A 3 inch, ASA type access port, centered in the left hand wall is standard.

Vacuum System

Chamber pressure is reduced by a two stage, oil sealed vacuum pump with a power off automatic suction line dive valve to prevent oil back streaming. Standard pressure control inside the workspace is manual using a climb and dive valve.


Chamber air is recirculated by one or more high volume, stainless steel axial fan(s) discharging through a hinged rear mounted guard and diffuser baffle to create a uniform environment around your test objects.

The fan is driven by a vertically mounted motor with dual ball bearing races driving a large diameter stainless steel shaft through a magnetically sealed shaft seal.

Fast-response sheath type heaters behind a radiation baffle raise chamber temperature as required.

A proportionally controlled, cascade, two compressor, refrigeration system utilizing modern environmentally friendly refrigerants cools the workspace. The system includes automatic hot gas bypass and suction cooling unloading as well as Bemco’s exclusive, high reliability coaxial cascade heat exchanger. All systems are water cooled, have thermal and current sensors on each compressor, as well as numerous safety and reliability protection systems for dependable operation.

Chamber humidity is increased by a Bemco valve isolated, and automatically vented on altitude, mass transfer vapor generator with a sight glass, low water, and automatic drain freeze protection. It can be shut-off and drained when very low humidity control is desired. The humidification system requires a source of demineralized but not deionized water. We recommend that you contact a local water conditioning company for a survey of your laboratory’s available water supply.

Chamber humidity is decreased by the direct injection of -73 C (-100 F) dew point dry air produced by a dual bed regenerative compressed air drier that includes an isolation valve, a safety setup valve, an inlet particulate and coalescing filter, and an outlet filter regulator. Humidity operation is limited to site pressure.

Standard Brooks Automation, Granville Phillips 375 Convectron Gauge Control

Each Bemco AFW chamber is furnished with a two channel microprocessor based programmable 1/4-DIN, solid state, 256-step ramping temperature controller with a 4-line LCD interface display and a large red LED display.

Temperature inside the AF chamber is sensed by a precision thermocouple. An RS232 and RS485 interface is standard. Heaters are interlocked with a separate heavy duty power contactor and a factory preset high temperature safety control.

Humidity is sensed by a direct reading, electronic humidity sensor accurate to + or - 2% RH over the dewpoint temperature range of -20 C to 85 C (-4 F to 185 F).

Vacuum is monitored by a Brooks Automation, Granville-Phillips Series 375 Convectron Gauge Controller. This instrument provides accurate vacuum measurements from atmosphere to 1 x 10-4 Torr. It features easy push button control and digital readout. For AF chambers, the RS-232 and RS-485 interfaces on the vacuum gauge control are standard.

An alternate is offered to provide a very accurate absolute pressure transducer combined with a display calibrated in feet of altitude. Click here to review our AI Display and Pressure Transducer Option.


Standard Bemco AFW chambers cool from 23 C (+73 F) to -65 C (-85 F) in approximately 60 minutes and heat from 23 C (+73 F) to +150 C (302 F) in approximately 45 minutes, both with the chamber empty.

Temperature control is + or - 1 C (+ or - 1.8 F) guaranteed, + or - 0.15 C (+ or - 0.25 F) typical. Humidity control is + or - 5% RH guaranteed, + or - 1% RH typical.

Humidity range is 5% RH to 95% RH, see chart. 95% RH at 85 C (185 F) maximum. Humidity systems operate without dewpoint limit from 5% RH to 95% RH over the range of 30 C to 85 C.

The standard AFW series chamber has the ability to reduce pressure from local atmospheric pressure to 8.2 Torr (equivalent to 100,000 feet altitude) in 20 minutes. Ultimate pressure is in excess of 0.13 Torr (equivalent to 200,000 feet altitude).

Standard system power is 230 VAC - 3 Phase - 60 Hertz on the AFW10 and AFW25 and 460 VAC - 3 Phase - 60 Hertz on the AFW50 and AFW80. All electrical wiring meets the United States National Electric Code. UL and CSA approved components are used where possible.

Optional Equipment

Optional Instruments

Controls are mounted on the side to prevent dripping from damaging the instruments. Available instruments include:

Available Literature Includes:

AF Altitude, Temperature/Altitude, and Temperature/Humidity/Altitude Chambers Literature Download Bemco AF Series, Altitude, Temperature/Altitude, and Temperature/Humidity/Altitude Chambers. Eleven standard models and a large number of optional systems. Document is 8 pages, 643 KB download.

Bemco Altitude Conversion Table Bemco Altitude Table. Conversion Table from equivalent feet and kilometers to Torr (mmHg), kiloPascals (kPa), and pounds per square inch absolute. Covers -1,000 feet to +250,000 feet in 5,000 foot increments. The data presented is based on the "US Standard Atmosphere, 1976 jointly developed by NOAA, NASA, and the USAF. It is an idealized, steady state representation of the Earth's atmosphere that assumes an average value for gravity. Document is 1 page, 108 KB download.

The systems described above are our Standard Models. We make custom equipment to your specifications.  Walk-in sized altitude, temperature, and humidity chambers are also available. Please look at our Bemco FL Series Page. If you have any questions, need assistance in preparing a specification, or have a technical problem you want help with, we are ready.  Our quotations and advice are free.

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