Storage types
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“Warehouse” covers buildings with very little in common. A dry goods distribution center, a minus-ten freezer and a vault of archive boxes all store things, but the equipment, the rules and the costs are completely different. Below are the main types you’ll run into in quotes and directory listings, followed by the ways goods are physically held inside a building.
Temperature and humidity
Start with the environment the product needs. Temperature drives most of the cost, since refrigerated and frozen space is more expensive to build and to run than dry space.
| Type | Typical range | Common products | What to check |
|---|---|---|---|
| Ambient / dry | Not controlled beyond normal building conditions | Packaged goods, hardware, apparel, paper | Roof condition, summer peak temperatures, pest control |
| Temperature-controlled ambient | Held within a band, e.g. 20–25 °C (68–77 °F) | Medicines labeled for controlled room temperature, chocolate, wine, some chemicals | Temperature mapping, continuous monitoring, alarm response |
| Chilled / refrigerated | At or below 41 °F (5 °C) for food; 2–8 °C (36–46 °F) for pharma | Dairy, fresh meat, produce, vaccines, biologics | Separate rooms for products with different needs, door discipline |
| Frozen | At or below 0 °F (−18 °C) | Frozen meat, seafood, vegetables, bakery, ice cream | Blast freezing capacity, defrost cycles, floor heating |
| Deep frozen / ultra-low | Well below 0 °F; specialist sites | Some seafood, ice cream held for long periods, specific biologics | Specialist equipment, backup power, product-specific protocols |
The food figures come from US guidance. The FDA Food Code uses 41 °F (5 °C) or below for cold holding of time/temperature-controlled foods, and the FDA’s consumer guidance recommends freezers at 0 °F (−18 °C). Warehouses often run colder than those limits. The number that counts is the one on the product’s own specification, set by its manufacturer. Each zone gets a fuller treatment, including humidity and how multi-temperature buildings are laid out, in cold storage temperature zones.
Some goods care more about moisture than temperature. Damp air can damage paper, cardboard, tobacco, seeds, leather and electronics, and produce dries out when the air is too dry. Ask whether humidity is controlled and logged, not only temperature.
Regulated storage
Some storage is defined less by its environment than by the rules that apply to it.
A food-grade warehouse keeps food apart from chemicals and other sources of contamination, runs a pest control program and follows sanitation and hygiene procedures. In the US, facilities that hold food for consumption in the country generally have to register with the FDA. Many food warehouses also hold a certificate under a third-party food safety scheme, because customers often require one.
A customs bonded warehouse holds imported goods under customs control, with duty deferred until the goods enter the domestic market. The US rules are in 19 CFR Part 19. Foreign-trade zones work on a related but separate legal basis, and the EU, the UK and Turkey each have their own customs warehousing procedures. Our guide to bonded warehouses and free trade zones goes further.
Flammable liquids, aerosols, oxidizers, corrosives and lithium batteries bring fire code, building code and workplace safety requirements with them. In the US, OSHA’s standard for flammable liquids is one of several that apply, alongside local fire codes. Hazmat-capable warehouses have segregated areas, specific sprinkler designs and trained staff. Send the safety data sheets before you ask for a quote.
Records centers store boxes of paper files, sometimes tape and film too, and offer indexing, retrieval and secure destruction. The building needs strong fire protection and access control. Temperature control mostly doesn’t come into it, apart from vaults for film and magnetic media. See offsite records storage.
Racking and stacking
Inside the building, the storage method decides how densely goods can be packed and how quickly any one pallet can be reached.
| Method | How it works | Suits | Trade-off |
|---|---|---|---|
| Floor (block) stacking | Pallets stacked directly on the floor | Few products in large quantities that can bear weight | Poor access to anything not on top or at the front |
| Selective pallet racking | One pallet deep, every pallet reachable | Many products, mixed volumes | Uses more floor space per pallet |
| Double-deep racking | Two pallets deep | Products with at least two pallets each | Needs reach trucks; rear pallet is blocked |
| Drive-in / drive-through | Forklifts enter lanes several pallets deep | High volume per product, often freezers | Last-in, first-out unless drive-through |
| Push-back and pallet flow | Pallets roll on carts or rollers within the lane | High volume per product with rotation needs | Higher cost per position |
| Mobile racking | Racks on rails, aisles open where needed | Freezers and cold rooms, where space is expensive | Slower access |
| Shelving and carton flow | Hand-picked bins and cases | E-commerce, spare parts | Low weight capacity |
| Automated storage (AS/RS) | Cranes or shuttles store and retrieve loads | High throughput, steady demand | Large capital cost, less flexible |
Freezers lean on dense methods like drive-in racking because every cubic foot of frozen space is expensive to build and to cool. You pay for it in stock rotation. When a lane is loaded and unloaded from the same end, the first pallet in is the last one out, which works against first-expired, first-out rotation.
Starting from the product
Pick the product first and the warehouse second. Write down the storage conditions from the product specification, including humidity and light. Note the regulatory status: food, pharmaceutical, hazardous, imported under bond, or general goods. Record the unit load, meaning pallet size and height, weight and whether pallets can be stacked. Add velocity (how many units move in and out each week, and how many different products there are), then shelf life and whether lot or expiry tracking is required.
With that profile written down, it becomes clear which buildings can do the job. The directory shows which services each listed operator offers.
Common questions
What temperature is cold storage?
There's no single figure. Chilled or refrigerated food storage is usually held at or below 41 °F (5 °C), the limit US food safety guidance uses for cold holding. Frozen storage runs at or below 0 °F (−18 °C), and the pharmaceutical cold chain commonly uses 2–8 °C.
Is ambient storage the same as dry storage?
Mostly. Ambient storage has no active temperature control beyond the building's normal heating or ventilation. Temperature-controlled ambient storage keeps goods within a set band, such as the 20–25 °C controlled room temperature used for many medicines.
What is a bonded warehouse?
A customs-approved facility where imported goods can sit without duty being paid until they're released into the domestic market. If they're re-exported instead, duty may never be due.
Do food warehouses need to be registered?
In the US, facilities that hold food for consumption in the country, warehouses included, generally have to register with the FDA and renew the registration every two years. Some exemptions apply.
What is the difference between selective racking and drive-in racking?
Selective racking lets a forklift reach every pallet directly, which suits a wide range of products. Drive-in racking stores pallets several deep in lanes. It packs more into the space, but only the front pallet of each lane can be reached.
Sources
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