Selection guide
What is a wash rack?
A wash rack is a platform a vehicle is driven onto so it can be washed over containment rather than over the ground. The washing is usually manual and high-pressure. The rack's job is to catch everything that comes off the vehicle — water, mud, oil, grit — and route it somewhere it can be treated.
Terminology
Wash rack, wash pad, containment pad
The words move around by region and by industry, which makes specifying one harder than it should be. Roughly:
- Wash rack — the general term, and the usual one in defence and heavy-equipment contexts. Covers both above-ground and permanent installations
- Wash pad — often implies a permanent concrete pad, though it is used loosely for above-ground steel pads too
- Containment pad / containment rack — the same object described by its purpose: containing the effluent
- Washdown bay / wash bay — common in Australia and in agricultural and biosecurity contexts; usually the whole facility, not just the platform
- Wheel wash — a different machine entirely. It cleans wheels and undercarriage at a site exit and does not wash the vehicle body. See wheel wash systems
Types
Above-ground or in the ground
There are two ways to build containment under a vehicle, and the choice is usually decided by how long the site will be there.
- In-ground / concrete — excavation, a reinforced slab, buried drainage and an interceptor pit. Durable, unlimited in size, and the right answer for a permanent depot. It is also a civil project with approvals, and it does not move
- Above-ground / modular steel — a raised platform with containment built underneath and ramps for access. Needs a level hardstand rather than excavation, goes up as a site task, and can be dismantled and relocated
- Modular above-ground takes that one step further: standard modules that combine to the pad size you need, so the same product covers a utility-vehicle pad and a multi-module plant pad
Sizing
The four inputs that decide everything
Every real quotation comes back to these. Two of them are usually easy; the two people skip are the ones that change the design most.
Vehicle dimensions
Length, width and height of the largest machine — which sets the pad area, the number of modules and how they are arranged.
Weight and loading
Gross vehicle weight places the machine in a duty class. Individual axle and wheel loads, tyre contact area and track loading are what the structure is actually calculated against.
Quantity and type of dirt
Light road film, construction mud and sticky mining clay are three different problems. This decides whether you need a sludge pump, a scraper conveyor, or neither.
Washing requirement
How many vehicles, how often, at what flow and pressure, and how long each wash takes. This sizes the water side — pumps, treatment capacity and storage.
Why contain it at all
Four reasons the water can't just run off
It is process wastewater
Wash water carrying detergent, hydrocarbons and sediment is not stormwater. Regulators generally treat it as process wastewater with its own rules — in the United States, construction effluent guidelines at 40 CFR 450.21 prohibit discharging equipment-wash wastewater from a site.
It undermines your own hardstand
Water repeatedly soaking into an unsealed or partly prepared base softens it, erodes it and reduces bearing capacity — which lets the wash area settle and puts the platform out of level.
It moves soil and seed
Material carried off one site on an undercarriage is the reason washdown and biosecurity controls exist. Containment is what makes a washdown auditable rather than just wet.
It is water you have already paid for
On a remote site, water is trucked in. Contained water can be treated and reused; water that runs to ground is bought twice.
Before you ask for a quote
What to have ready
Send these and you will get a configuration back rather than a set of questions:
- The machine list — types, models and weights, with axle or wheel loads if the OEM data is to hand
- The largest machine's overall length and width, and its ground clearance if it is low
- What is on the machines: road dirt, construction mud, clay, mining fines, hydrocarbons
- Vehicles washed per day or per week, and how long an operator spends on each
- The hardstand you have — area, surface and whether it is level
- Water source and what you want to do with the treated water
- Whether the site is permanent, or the rack has to move with the project
The range
KKE portable modular wash racks
One 2200 × 3000 mm galvanised module, three structural classes, and the water side sized to match. Start from the heaviest machine on the pad.
Light duty
Up to approximately 2 t — golf carts, ATVs and UTVs, small pickups and light plant.
Light duty rackMedium duty
Approximately 18–25 t — commercial and dump trucks, backhoes, excavators and telehandlers.
Medium duty rackHeavy duty
Up to approximately 80 t — mining support and heavy earthmoving equipment, armoured vehicles.
Heavy duty rackThe water side
Containment under the deck, solids out before treatment, and a containerised plant that returns water to the wash guns.
Water recyclingFAQ
Common questions
Is a wash rack the same as a wheel wash?
No. A wheel wash cleans wheels, tyres and undercarriage as a vehicle leaves site, usually automatically, to stop mud being tracked onto public roads. A wash rack is a platform for washing the whole machine, usually by hand with high-pressure lances. Plenty of sites run both — a wheel wash at the gate and a wash rack at the workshop.
Does an above-ground rack need a concrete base?
It needs a suitable level hardstand, sized for the machines being washed — not an excavated, reinforced and drained wash slab. That is the saving. Anyone telling you an above-ground rack needs no ground preparation at all is setting you up for a settlement problem.
Can a wash rack be moved between sites?
A modular bolted rack can. Modules are designed for container transport and hot-dip galvanised so they survive being dismantled, shipped and reassembled. A concrete pad cannot, which is the main reason temporary sites choose steel.
How do I know which duty class I need?
Start from the heaviest machine that will use the pad, then confirm with axle and wheel loads rather than gross weight alone. Our engineers do that check before quoting — see the light, medium and heavy duty classes for the indicative bands.
Do I need water recycling with it?
Not always. It depends on what your jurisdiction allows you to discharge, how much water costs to get to the site, and how dirty the water is. On remote and high-volume sites, recycling usually pays; on a low-volume site with a legal discharge route, containment and settling may be enough. See wash rack water recycling.
Get started
Have our engineers specify it for you
Send the machine list and the site, and we will come back with a duty class, a pad layout and pricing.