Save today on our selection of new and pre-owned lab equipment!

Forma™ Environmental Chamber Model 3911, 311.5 L, SS with Humidity Control, 208 - 220V, 60 Hz

Quote Required
Financing By 
Perform a variety of applications withThermo Scientific Forma environmental chambers, which can be configured for a variety of purposes and are available in multiple capacities. With a wide range of accessories and years of experience in constructing cabinets, we can construct units to match your

Broad Range of Features and Controls:

  • Wide temperature range of 0° to 60°C that enhances the flexibility of the unit
  • Relative humidity control via steam generator from above ambient to 95% at 37°C (not available w/Cat. No. 3920)
  • Sophisticated digital controls
  • Programmable ramp and soak cycles for temperature and RH†
  • Durable cabinets with true laminar airflow through side plenums for extremely tight uniformity
  • Phenolic-coated evaporator for use in applications that create corrosive byproducts
  • Manual control of defrost and refrigeration cycles
  • Visible/audible safety alarms alert to over- and undertemperature conditions, deviation of humidity from set parameters (except Model 3920)

Durable Construction:

  • Cold-rolled steel, powder-coated cabinet
  • 2? (5.1cm) thick, CFC-free, foamed-in-place polyurethane insulation
  • Stainless-steel interior with solid stainless-steel adjustable shelves
  • Directed horizontal airflow system for excellent uniformity
  • Locking swivel casters for easy mobility during installation and cleaning
  • Leveling feet for stability and added safety in the lab

Broad Range of Options:

  • Interior lighting for Models 3920, 3940 and 3949 (Optional)
  • Reinforced shelving and flooring for heavy loads
  • Heatless dryer for lower humidity levels
  • Access ports for probes, sensors
  • Interior convenience receptacles
  • CO2 (IR sensor)
  • 6? and 12? temperature chart recorder
  • Other custom options available

Compatible with:

  • Recorders (197075, 198036, 198039, 198042, 201144, 201145, 201146, 201147)
  • Reach-In/Environmental Chamber Solid Stainless-steel Shelf (224139)
  • Reach-In/Environmental Chamber Perforated Stainless-steel Shelf (224155)
  • Reinforced Stainless-steel Shelf (224161)
  • Fixed Reinforced Stainless-steel Shelf for two shakers (1900005)
  • Stainless-steel Door Glass Cover, factory installed (190591)

Recommended for:

Ideal for growth, stability and shelf-life testing applications

Ordering Information

† Humidity controller available on 3940/3949, 3911/3913 only


Amperage15 A
Capacity (English)11 cu. ft.
Certifications/ComplianceICH, FDA, TAPPI, ASTM™
Depth (English) Interior27 in.
Depth (English)32 in.
Depth (Metric)81.3 cm
Depth (Metric) Interior68.6 cm
Capacity (Metric)311.5 L
Chamber MaterialStainless Steel
Dimensions (D x W x H) Interior27 x 31 x 24 in. (68.6 x 78.7 x 60.9 cm)
Temperature Range (Metric)0°C to 60°C
Relative Humidity95%
MaterialPowder-coated Cold Rolled Steel
DisplayDigital Dual LED
Electrical Requirements208/220 V, 60 Hz
Frequency60 Hz
Height (English)51.5 in.
Height (English) Interior24 in.
Height (Metric)130.8 cm
Height (Metric) Interior60.9 cm
Humidity ControlMicroprocessor, PID
Humidity DisplayDigital, dual LED (direct set and read in % RH)
Humidity Accuracy±5.0%
Humidity Resolution0.01
Humidity SensorBulk polymer
Humidity SourceSteam generator; initial fill approx. 1 qt. (1L)
Input Water PressureWater Inlet Gravity to 40psi
No. of Shelves3 supplied/11 max.
ProgrammabilityTemperature ramp and soak, up to 24 steps
RefrigerantCFC-free, R134A
Temperature Accuracy±0.1 at 25° to 37°C
Temperature Resolution0.1°C
Temperature SensorRTD
Temperature Uniformity±0.3 at 25° to 37°C
Voltage208/220 V
Water Consumption0.25 gal./hr. input water volume
Water Resistivity50kilohm to 1megohm resistance
Width (English)38 in.
Width (English) Interior31 in.
Width (Metric)96.5 cm
Width (Metric) Interior78.7 cm
CO2 Sensor TechnologyIR Sensor
LightingOptional Interior Lighting
TypeEnvironmental Chamber
Unit SizeEach
More Information
Voltage 208/220 V, 60 Hz


We encourage you to explore the wealth of information available on our product pages. To ensure you're making the right choice, please:

  • Review the product specifications.
  • Consult with the manufacturer or
  • Get in touch with our dedicated sales and technical teams.

To ensure a seamless experience for all, we acept returns for new  items. All returns are subject to a 20% restocking fee. Please double-check that the equipment you're selecting meets your requirements.


When your order arrives, we recommend a thorough check for any potential damage before finalizing the delivery process:

  • Before signing any delivery documentation, ensure your equipment is in perfect condition.
  • If you spot any damage, kindly decline the delivery, and make a note of the damage on the Bill of Lading. Alternatively, inform the UPS/Fedex driver so they can document the reason.

If there are any concerns, please contact us within 48 hours of receipt. If damage is discovered after accepting the delivery without prior documentation, please address any claims directly with the delivery carrier.


Should you encounter any issues with your instrument that can't be addressed, you may return it within 30 days. Please note that certain products are subject to a 20% restocking fee. Customized items are final sale and ineligible for return. When we receive returned items, they undergo a comprehensive inspection and testing. We retain the right to decline returns for items that have been mishandled or improperly used.