Thermo Forma 3940 Refrigerated Environmental Chamber

2026-01-29T09:30:27-05:00

Vendor: Thermo
Type: Incubators
Price: 7900.00

Thermo Forma 3940 Refrigerated Environmental Chamber

Thermo Forma Reach-in refrigerated incubator chambers are perfect for applications that require temperature control below and/or above ambient, e.g. storage, testing, and incubation at low temperatures. The refrigerated incubator chambers meet International Conference on Harmonization (ICH) guidelines for drug substance and product storage testing. The units are ideal for drug stability studies, shelf-life testing for packaged products, insect and other large-scale biological research.

Thermo Forma 3940 features

Capacity: 29 Cu. Ft.

Temp range: 0°C to 60°C

Humidity range: above ambient to 95%

Solid door

90-day warranty

These chambers feature a 0°C to 60°C (32°F to 140°F) temperature range that can be set in 0.1°C increments. The broad temperature range, and optimum temperature uniformity and recovery contribute to an ideal test environment, even when the chamber contains large product loads and low-output, heat-generating equipment. They also feature a humidity control system, which allow you to set the RH level between ambient and 95% in 1% increments.

The humidity system requires a water purity in the resistance range of 50K to 1M Ohm/cm, or a conductivity range of 20.0 to 1.0 uS/cm. The water source can be either pressurized (up to 40PSI) or unpressurized.

If an in-house water supply of the required purity range is not available, an alternate method can be used. A large, vended carboy (5 gal. minimum) of water in the required purity range can be placed on top of the unit.

This combination directs air across the surface of each solid shelf. Even when filled with samples or equipment, each shelf receives a consistent flow of conditioned air for optimum temperature uniformity and recovery. As opposed to a horizontal airflow system, top-to-bottom (non-directed) airflow systems use a top-mounted fan to push air down through wire shelves.

Thermo Forma 3940 - additional features

Temperature uniformity and recovery can deteriorate quickly when shelves are filled because air movement is blocked. That variation in temperature, alone or when combined with frequent door openings, may compromise environmental conditions, or make process validation difficult.

The Thermo Scientific Directed Airflow System promotes an ideal growth environment. The enhanced design includes a positive pressure feed plenum on the right side of the chamber and a negative pressure return plenum on the left to distribute the airflow uniformly throughout the chamber.

Thermo Forma 3940 Refrigerated Environmental Chamber Testing

Most of our equipment is used and reconditioned. All of our incubators are used and reconditioned. We test incubators using a calibrated digital chart recorder to verify the accuracy of temperature controls and readouts. We replace any hardware or parts as is necessary and clean all incubators thoroughly prior to shipment.

Thermo Forma 3940 Pictures

The photos above are representative. Please bear in mind that the equipment shown is currently in storage in our warehouse. In addition to testing each machine we will clean all the equipment thoroughly prior to shipment.

We often have multiple units of each model in stock. Sometimes we're unable to feature photos of every single unit. At your request, we can provide photos of the equipment in your order after testing and cleaning.

Thermo Forma 3940 Refrigerated Environmental Chamber – specifications

External dimensions | 38”W x 32”D x 88.5”H
Internal dimensions | 31”W x 27”D x 60”H
Chamber volume | 29 cu. ft.
Temperature range | 0°C to 60°C
Temperature accuracy | ±0.1 at 25° to 37°C
Temperature resolution | 0.1°C
Temperature uniformity | ±0.3 at 25° to 37°C
Humidity range | above ambient to 95%
Humidity accuracy | ±5.0%
Humidity readability | 1%
Electrical requirements | 208/220 V, 60 Hz

For inquiries about the Thermo Forma 3940 Refrigerated Environmental Chamber, please give us a call at 978-521-2221, or fill out the form on this page.

Thermo Forma 3940 Incubator – Frequently Asked Questions

What applications is the Thermo 3940 environmental chamber used for?

The Thermo Forma 3940 is designed for precise control of temperature and humidity in both above-ambient and sub-ambient conditions. In other words, this model can both heat and cool, and provide stable humidity, making it a versatile option for a wide range of uses.

The 3940 is commonly used for pharmaceutical stability testing (ICH-compliant), shelf-life studies and packaging validation, microbiology and biological incubation, environmental and insect research, and any other application requiring a large chamber with tightly controlled temperature and humidity.

Labs searching for used environmental chambers often choose the 3940 due to its reliability, large capacity, and regulatory compatibility.

Explore more options: Browse our full selection of used environmental chambers to compare available inventory.

What makes the Thermo 3940 different from other used environmental chambers?

A key advantage of the Thermo Forma 3940 environmental chamber is its directed airflow system. This provides uniform air distribution across all shelves without large variance in temperature throughout the chamber. In other words, the airflow creates temperature uniformity throughout the chamber. It also improves faster recovery after door openings and stable performance under heavy loads.

Compared to many used environmental chambers that rely on top-down airflow, the 3940 offers superior uniformity, which is critical for stability testing and GMP environments.

Is the Thermo 3940 suitable for pharmaceutical stability testing?

Yes. The Thermo 3940 environmental chamber is commonly used in:

GMP and GLP laboratories

ICH stability protocols

FDA-regulated environments

Its precise control and programmability make it a top choice among buyers searching for used environmental chambers for stability testing.

What features of the Thermo 3940 support controlled environments and compliance?

Key features include:

Microprocessor-based control system

Programmable ramp/soak profiles

High/low temperature safety alarms

Humidity control via steam generator

Remote monitoring outputs

These features help labs maintain validated, auditable environmental conditions, especially important when purchasing used environmental chambers for regulated or other highly sensitive workflows.

How does the Thermo 3940 compare to similar models?

Thermo Forma 3940 vs 3920

Similar capacity and temperature range

3940 often includes more advanced programmability

3940 features humidity; standard 3920 does not

Both are common in the used environmental chamber market

Thermo 3940 vs Percival Chambers

3940: Better for pharma stability and uniformity

Percival: Better for plant growth and lighting applications

Thermo 3940 vs Binder Chambers

Thermo: Strong airflow and durability

Binder: Often newer interface, but higher cost

Why buy a used and refurbished Thermo 3940 environmental chamber?

Buying a used environmental chamber like the Thermo 3940 offers:

Significant cost savings vs. new

Proven long-term reliability

Availability of replacement parts and service

Immediate availability (no long lead times)

This model remains one of the most sought-after used environmental chambers due to its performance and durability.