WiFi for warehouses and industrial sites

Warehouses and industrial sites are among the hardest places to build reliable WiFi. Metal racking, changing stock, high ceilings and moving vehicles all affect signals, and the devices that depend on the network, such as scanners and vehicle-mounted terminals, are often less capable than office laptops. A good design starts with those devices and the way the building is actually used.

What makes these sites different

Racking and stock

Steel racking and shelving block and reflect signals, turning each aisle into a corridor where coverage depends on what is stored. Stock with high water content, such as beverages or food, absorbs signal. Liquids and metal goods can make one aisle behave very differently from the next, and coverage can change as inventory levels rise and fall through the year.

High ceilings

Access points mounted near a high roof are far from the devices on the floor, and the signal has to come down through the tops of the racks. Omnidirectional ceiling access points often perform poorly here. Directional antennas aimed down aisles, or lower mounting on columns or racking, are common solutions.

Mobile devices and vehicles

Handheld scanners, wearable computers and forklift-mounted terminals move constantly, so roaming between access points must be fast and reliable. These devices often have smaller antennas and lower transmit power than laptops, and some support only older WiFi standards or limited channels. See WiFi roaming and handoff.

Harsh conditions

Dust, moisture, temperature extremes in unheated or refrigerated areas, vibration and washdown areas all call for suitably rated access points and enclosures. Freezers and coolers can also behave like metal boxes, needing their own coverage inside.

Interference

Industrial equipment, older wireless systems and neighbouring tenants in shared buildings can all add noise. Some plants run proprietary radio systems that share the same bands.

Design approach

1. Ask why. List the applications and devices: warehouse management system scanners, voice picking, vehicle terminals, cameras, RFID and asset tracking, and office users.
2. Find the weakest critical device. Design coverage and roaming to what that device needs and supports, including bands and channels.
3. Survey on site, with stock in place. A predictive model cannot account for racking and inventory reliably. On-site measurements, including access point on a stick testing in representative aisles, are essential. See Predictive vs on-site WiFi surveys.
4. Choose antennas and mounting. Use directional antennas down aisles where needed, and mount where racks, sprinklers and lights will not obstruct the signal.
5. Plan roaming and channels. Make sure each area has secondary coverage so devices can move without dropping, and set channels the devices can actually use.
6. Validate under real conditions. Test with the actual devices, during operations, along the routes they travel.

Symptoms and likely causes

A worked example

A distribution centre adds a new section of high-bay racking for slow-moving stock and converts part of the building to a cooler. Pickers already report scanners losing their session in some of the existing aisles.

The survey is done during a normal shift, with racks loaded, using the same scanner model the pickers carry. It shows that the roof-mounted access points leave the lower levels of the fullest aisles well below the scanner's needs, and that there is no second access point audible in the middle of the longest aisles. Inside the cooler, almost no signal gets through the insulated panels.

The design adds directional access points at the ends of the long aisles, aimed down them, so each aisle is covered from both ends. Access points over the new high-bay section are mounted lower, on the columns over the aisles. The cooler gets its own access point rated for the temperature, cabled through a sealed penetration coordinated with the refrigeration contractor. All mounting is done from a suitable lift with traffic control in the aisle. The validation survey repeats the original routes with the same scanner.

What to record during the survey

• Racking heights, aisle widths and what is typically stored in each zone.
• Stock levels on the day, so later surveys can be compared fairly.
• The device models used for testing, and their supported bands and channels.
• Possible mounting points: columns, beams and rack uprights, and what is permitted on each.
• Cold, dusty, wet or washdown areas that need rated equipment.

Extras: tracking, yards and outbuildings

Many sites also want RFID or WiFi-based asset tracking, which often requires each location to be heard by several access points. See RFID and asset tracking. Yards, loading docks and outbuildings may need outdoor access points or point-to-point links back to the main building.

Installation safety

Mounting access points in warehouses usually means working at height on lifts or ladders above active aisles, near racking, lighting and sprinkler lines. That work needs proper planning: trained and authorized lift operators, fall protection where required, traffic control to keep forklifts and pedestrians away, and coordination with site operations. Installers should follow the site's safety rules and the occupational health and safety rules of the province.

Keeping it working

Warehouses change. Racking is reconfigured, stock levels shift and new device models arrive. Record the design assumptions, keep as-built drawings of access point locations, and resurvey after significant changes or when users report new dead spots. Protect access points from forklift damage, and keep spares of the models and mounts in use.

How ehZee can help

We design warehouse and industrial WiFi around the devices and operations that depend on it, using on-site measurements with AirMagnet Survey Pro and our checklist covering metal structures, neighbouring networks, SNR and RFID or asset tracking. Our WiFi design and build service takes the network from survey to a validated installation.

Common questions