Non-Slip Coatings
Steel floors, decks and panels are used in many applications from train steps to oil platforms. Untreated, this steel can become very slippery, especially in wet conditions. In many applications, corrosion is also a hazard. Safe walking and industrial operating conditions are vital to personal safety and corporate productivity. Now there’s a durable solution for both of these problems. The MSSA 28E coating is used for non-slip applications. The incredibly durable non-slip metallic coating has been used on baggage handling ramps and walkways in airports, as well as ferry loading ramps and walkways in a new sporting stadium in the UK. Untreated steel surfaces can become very slippery, especially in wet conditions, and are prone to corrosion. To ensure safe walking and industrial operating conditions, vital to personal safety and corporate productivity, the MSSA 28E coating provides a durable non-slip anti-corrosion coating.
Image Provided Courtesy of Metal Spray Hungary
What Normally Happens?
Traditionally, steel structures are hot dip galvanised, or painted, to protect against corrosion. The disadvantage of hot dip galvanising is that the surface can become slippery and it does not easily accept paint without the need for special primers. Painting this type of surface, which is sometimes applied with grit inclusions, also has its disadvantages. The surfaces can degrade quickly in heavy use, resulting in corrosion and an increased slip hazard.
Many large steel structures, including oil platforms, refineries and bridges, have been routinely protected against corrosion by thermal spray aluminium (TSA), zinc or an alloy of the two.
Why Isn't this Good Enough?
While providing unrivalled corrosion protection in very aggressive corrosive environments, pure TSA is not durable enough to prevent long term wear on floor plates.
What Should Happen?
Ideally, steel structures need a durable coating that protects against both slip and corrosion and that’s exactly what the MSSA 28E coating does.
- Provides a suitable level of grip to avoid personal slips or industrial skidding.
- Provides comparable corrosion protection to aluminium as used in extremely aggressive environments.
- Provides easy application by a long-standing process covered by international standards.
28E is applied using the arc spray process with the ARC 145 system. In the arc spray process the raw material, in the form of a pair of metallic wires, is melted by an electric arc. This molten material is atomised by a cone of compressed air and propelled towards the work piece. Upon contact, the particles flatten onto the surface, freeze and mechanically bond, firstly onto the roughened substrate and then onto each other as the coating thickness is increased. Coating thickness can range from around 50 microns up to several hundred microns or even millimetres for some metals. Typically, metal sprayed corrosion protection coatings vary from 100 to 350 microns.
A 28E coating is a thermally sprayed coating that can be applied with a rough texture and has excellent non-slip properties, while being extremely hard and resistant to wear.
The resulting coating is corrosion resistant and because of its durability, site owners can be confident that once applied, they can forget about rust or slipping for many years.
28E Non-Slip Durability Testing
28E coatings have been tested with a Pendulum Coefficient of Friction (CoF) tester, in accordance with independent British Standards and UK Health and Safety Executive guidelines. The HSE guidelines suggest that a floor coating with a Pendulum Test Value (PTV) greater than 36 will have a low slip potential in pedestrian areas. To prove the durability of the coating, steel plates were coated and tested as above. The coated plates were then walked on by a standard shoe on a robotic walking machine. The plate was rotated after each step to simulate walking in a straight line and around corners. The PTV was checked before walking and at 250,000, 500,000, 750,000 and 1 million steps. Sealed and unsealed plates were tested in wet and dry conditions.
| Un-Sealed Sample | Sealed Sample (epoxy) | |||
| Cycles Completed | Pendulum Test Dry Value | Pendulum Test Value Wet | Pendulum Test Value Dry | Pendulum Test Value Dry |
| Initial | 80 | 75 | 72 | 66 |
| 250,000 | 66 | 50 | 70 | 63 |
| 500,000 | 65 | 49 | 71 | 61 |
| 750,000 | 64 | 43 | 69 | 60 |
| 1,000,000 | 64 | 41 | 68 | 58 |
Pendulum Test Values obtained in accordance with BS7976-2:2002
| Application | Width of Footfall Route | Typical Footfalls/Day | Life with a Low Slip Potential |
| Light Commercial (Small Office) | 2.4m | 1,000 | 21.8 years |
| Heavy Commercial (School) | 1.5m | 2,500 | 5.6 years |
| Heavy Commercial (Hospital) | 4.5m | 3,500 | 11.6 years |
The coatings tested were sprayed to produce a surface texture that would wear well but not be too rough for pedestrian surfaces. If the surface has too much grip on pedestrian areas, it can cause a trip hazard. However, in some industrial applications, it is desirable and possible to spray a coating that has a rougher texture and more grip.
28E Corrosion Testing
28E has undergone a range of accelerated corrosion testing. This offers a comparison of the performance between the 28E coating and 99.5% aluminium that has offered corrosion protection for several decades in harsh, corrosive environments around the world. Two tests were undertaken by an independent research laboratory:
- Galvanic corrosion tests for 1 week.
- Neutral salt spray corrosion tests for 1000 hours.
The latter was performed in accordance with ASTM B117. It was concluded that in both tests, the corrosion protection performance of the 28E was comparable to 99.5% aluminium, enabling confidence that the coating will provide excellent corrosion protection in harsh environments.
This article was published on the Offshore Technology website and is Available Here.
