Electrodeposition Tank Handrails: Specifying GRP for Paint Shop Platforms and Walkways
A maintenance walkway around an electrodeposition tank sits in one of the more demanding environments a handrail or access platform will ever be specified into. It is exposed to the tank’s own chemistry, to heat from adjacent curing ovens, to condensation and humidity, and to an electrical process that makes conductivity a genuine hazard rather than a theoretical one. Steel handles none of this well without a maintenance regime that most paint shops would rather not carry.
Engineered Composites has manufactured, fabricated and stocked glass reinforced plastic in the UK since 1986, and GRP handrails, walkways and grating are specified into exactly this kind of application because the material solves the problem at source rather than managing it after the fact. This piece sets out what an electrodeposition, or ED, tank actually puts a walkway through, and why GRP has become the specification of choice for the platforms, grating and handrails built around it.
A Different Kind of Immersion
In electrodeposition coating, the vehicle body acts as the cathode, immersed in a bath of deionised water carrying dispersed resin and pigment, with a DC voltage typically in the 100 to 400 volt range applied between the body and anodes positioned around the tank. The coating is self-limiting: as the film builds it insulates the surface and deposition slows, which is exactly why ED coating is used ahead of conventional spraying, it reaches into box sections and cavities a spray gun cannot. Ahead of the ED bath itself, pretreatment stages, degreasing and phosphate conversion, run their own separate chemistries, typically an alkaline cleaner followed by a mildly acidic phosphating stage, each with the same implications for anything built around them.
The process also generates hydrogen at the cathode, an inherent byproduct of the electrochemistry rather than a fault condition. It is managed through local exhaust ventilation to keep concentration well below the lower explosive limit, but its presence is precisely why the materials specified around an ED tank need to be chosen with more care than a standard industrial platform would require.
What the Walkway Has to Survive
Chemical and Thermal Resistance
A walkway or platform positioned over or beside an ED tank is in near constant contact with bath chemistry, whether through splash, mist or simple humidity, and with the acidic and alkaline chemistries of the pretreatment stages either side of it. GRP’s resistance to acids, alkalis, fresh and salt water, ethylene glycol, and fuel oils covers that full range without a special resin grade, and because the material’s structure and its resistance to attack are one and the same thing, there is no applied coating to fail and start the process of corrosion underneath it, the way there is with painted or galvanised steel.
Heat is the other factor. Curing ovens sit close by in most paint shop layouts, and a modular GRP system rated to a continuous operating temperature of 90°C, with short term tolerance to 130°C and full serviceability down to minus 50°C, holds its mechanical properties across that range without softening or distorting.
Platforms and Grating Underfoot
The grating underfoot matters just as much as the rail above it. GRP access platforms and anti-slip GRP grating give a slip-resistant surface in what is often a wet or oily working area, at around a quarter of the weight of an equivalent steel structure, which makes handling and installation considerably easier within the confined geometry of a tank surround.
Non-Conductive by Design
Non-Conductivity and Hydrogen Risk
No Hot Works, No Welding, No Site Painting
There is a second, more practical advantage that matters just as much on a live paint shop floor. Our modular GRP handrail system is assembled entirely by bolted mechanical connection using hand tools, so no hot works, welding permits, site cutting of metals or site painting are required within the tank. On a production line where hot works permits are tightly controlled and any site-applied coating risks contaminating a controlled paint environment, that is often the difference between a straightforward refurbishment and a lengthy permit process. Where the confined space itself needs a formal entry point rather than just a guarded walkway, GRP ladders and steps extend the same non-conductive, corrosion-resistant specification down into the tank surround.
Passing the Crater Test
How the Colour Is Achieved
Any unfamiliar material brought into a paint shop has to clear a materials approval process, and in most facilities that means a crater test before anything is signed off. GRP handles this cleanly because there is nothing on its surface to fail the test in the first place. Pigment is dispersed into the resin before the glass reinforcement is wetted out, so colour runs through the full wall thickness of the tube rather than sitting as an applied layer. Nothing is sprayed, dipped, brushed or bonded onto the surface after manufacture, and a cut end or a drilled hole reveals exactly the same coloured material as the outer surface. There is no coating to chip, contaminate the bath, or trigger a failed approval.
Standards and Accreditations
The standards framework behind the product gives a materials approval team something concrete to check against. Our modular handrail system has been independently tested by the Engineering Department at Lancaster University to BS 4592-0:2006+A1:2012 for general duty loading, and the pultruded profiles are manufactured to EN 13706-2 and EN 13706-3. Engineered Composites is manufactured under an ISO 9001:2015 registered quality system, and holds RISQS, JOSCAR and Cyber Essentials Plus accreditation, the last of which is increasingly relevant as automotive supply chains extend materials approval into cyber security as well as technical compliance.
What This Looks Like in Practice
We were recently asked to quote for replacing the handrail on a maintenance walkway inside an ED tank at a UK vehicle manufacturer’s paint shop. The two questions that mattered most to the customer were not about load rating, they already understood the standard modular system met the duty class required. They wanted to know how the colour was achieved, because every unknown material entering their paint shop had to be crater tested, and they wanted confirmation of chemical resistance against their specific bath chemistry. Both are exactly the questions this piece has set out to answer, and both point to the same underlying fact, that GRP was already the right material for the platform it was replacing, for the same reasons it would be specified new.
Specifying for the Environment It's Built For
An ED tank walkway is not a standard industrial platform with an unusual name. It sits in a chemically active, electrically sensitive, heat exposed environment, and the materials specified into it need to answer all three conditions at once rather than trading one off against another. GRP does that by design rather than by maintenance schedule, corrosion resistant without a coating to fail, non-conductive without an earthing requirement, and dimensionally and chemically stable enough to pass the same crater test a new paint colour would face.
Speak to the team at Engineered Composites to find out how GRP handrails can meet your project requirements.