The Scientemp 40-21EX is a 21 cu ft low-temperature chest freezer from Scientemp's Super Cold (0 °C to -40 °C ~ -45 °C) line, reaching 0 °C to -40 °C (-40 °F). It ships with an Analog display, a temperature alarm, a key-locking door and casters and single-stage R-404A refrigeration with manual defrost - a premium mechanical-refrigeration freezer that is fully customizable to the application. This is the explosion-proof (EX) configuration, built for installation in hazardous (flammable-atmosphere) locations.
Key Specifications
| SKU | 40-21EX |
| Type | Chest-style laboratory freezer - explosion-proof |
| Temperature range | 0 °C to -40 °C (-40 °F) |
| Capacity | 21 cu ft |
| Exterior dimensions | 47"H x 91"W x 36.5"D (includes handle & hinges) |
| Interior dimensions | 32"H x 60"W x 20"D |
| Insulation | Urethane foam |
| Refrigeration | R-404A |
| Compressor | 3/4 hp (single stage) |
| Defrost | Manual (cold-wall evaporator) |
| Temperature controller | Analog display |
| Alarm | Not itemized in the EX spec table - confirm at quote |
| Door / lock | Key-locking |
| Casters | 3" locking and 3" non-locking casters |
| Running amps | 6 A (230 V) |
| Hazardous-location rating | Class I, Division 1 - Group C & D |
| Voltage (this SKU) | 230 V / 60 Hz or 230 V / 50 Hz, single phase (explosion-proof build) |
| Voltage options | 230 V / 60 Hz, 230 V / 50 Hz (explosion-proof build) |
Application Profile
At 0 °C to -40 °C (-40 °F), the Scientemp 40-21EX covers the *super-cold* band that many enzymes, competent cells, tissue samples and reagents require for stable long-term storage below the reach of a standard -20 °C freezer. Single-stage R-404A mechanical refrigeration reaches these set-points without liquid nitrogen or cascade complexity, and the Analog display provides closed-loop control suited to valuable inventories. The 21 cu ft chest format holds cold well during access because dense cold air settles into the cabinet rather than spilling out when the lid is raised (see cold-storage).
Every Super Cold is customizable: access ports (1", 2" or 4"), ramp/soak control, CO2 and LN2 back-up systems, stainless-steel interior, observation window, and internal heater/fan are brochure-listed options - so the freezer can be specified to a protocol rather than bought off-the-shelf. Choose capacity by sample volume and set-point by the coldest material you store; for -80 °C-class work, step to the Ultra Cold line (see low-temperature-freezer-selection).
Explosion-proof build. This EX model is rated Class I, Division 1 - Group C & D per the Scientemp brochure - built for storing or siting near flammable solvents and volatile materials in a hazardous-classified location. It uses an analog temperature controller and 230 V single-phase power. Confirm your area's electrical classification matches the unit's rating before specifying.
Frequently Asked Questions
What temperature does the Scientemp 40-21EX reach?
Its working range is 0 °C to -40 °C (-40 °F). It reaches these set-points with single-stage R-404A mechanical refrigeration.
How much can it hold?
The 40-21EX has a 21 cu ft interior measuring 32"H x 60"W x 20"D. Exterior dimensions are 47"H x 91"W x 36.5"D (includes handle & hinges).
Is the 40-21EX certified for hazardous locations?
Yes - the brochure states an explosion-proof rating of Class I, Division 1 - Group C & D. Confirm this matches your facility's electrical area classification before ordering.
Is defrost automatic?
No - like all Scientemp chest freezers, the 40-21EX uses manual defrost with a cold-wall evaporator, which avoids the temperature swings of an auto-defrost cycle for stable long-term storage.
Can it be customized?
Yes. Brochure-listed options include access ports, ramp/soak control, CO2/LN2 back-up systems, stainless-steel interior, observation window and internal heater/fan (option availability varies by model). Specify these on the quote.
Ordering & Configuration
The Scientemp 40-21EX is built-to-order laboratory refrigeration; request a quote to confirm configuration and pricing. At quote, verify: set-point vs. the coldest material you store, capacity against your sample volume, voltage/electrical supply, any options (access ports, ramp/soak, CO2/LN2 back-up, stainless interior, monitoring), and freight/lead time for a unit of this size and weight. For this explosion-proof model, confirm the certified hazardous-location rating against your facility's electrical area classification before purchase.
Warranty: Per Scientemp standard terms - confirm at quote.
Positioning: the Scientemp 40-21EX is the 21 cu ft explosion-proof Super Cold (-40/-45 °C-class) chest freezer - for cold storage in hazardous, flammable-atmosphere locations. Confirm the certified Class/Division/Group rating against your site before purchase; the standard non-hazardous builds (e.g. 40-12, 45-6.8) apply where an EX rating is not required.
