Food factory flooring: best practice advice

04 July 2021

A recent BASF/Master Builders solutions whitepaper document sets out to identify the best practice for floor design and specification to achieve a long-lasting functional flooring solution in food production areas. Food Processing reports.

It is no surprise to hear that process area floors in the food and beverage industry need to be fit for purpose and durable to provide a safe and hygienic production environment. Flooring has several different functions in a food factory – it must provide a hygienic and easy to clean surface; it must not support biological growth; it needs to offer a safe working environment and must be durable, which may require resistance to chemicals and thermal shock, as well as mechanical abrasion and impact.

As part of its HACCP quality system a food producer must ensure that a floor will not compromise food safety. The easiest way to do this is to use a flooring system which has appropriate third-party certification for use in food handling facilities. Also the chosen floor should be dense, impervious and with bacterial cleanability comparable to stainless steel.

Flooring should also have been tested to ensure that it does not support the growth of bacteria or mould so always check with the provider to ensure that floors have been independently tested to confirm their hygienic performance.

The floor must provide a safe working environment for operatives so it needs an appropriate level of slip resistance. There are two widely used standards for measuring the slip resistance of floors — the ramp test described in DIN51130 and the pendulum test described in EN13036-4. The correct level of slip resistance, for any given area will depend upon activities taking place – BRG181 gives specific guidance here.

Durability

Durability comes from a combination of physical and chemical properties. Resin floors made with the same type of resin binder can have very different properties, depending on the formulation of the mortar and in particular the resin content. Low resin content materials will often rely on a thin surface sealcoat for their hygienic properties. Such a surface coat has a short life expectancy, especially when subject to hard wheeled traffic; once it has gone the mortars underneath offer poor durability, chemical resistance and cleanability.

Avoid the use lean resin mortars to produce coved skirting details as they have low resin content which also makes them porous. When such mortars are used on insulated panel walls bacteria and moisture can pass through a cove, under a wall and through to the other side of the wall to contaminate the adjacent environment. It is important to use resin rich thixotropic coving mortars which are dense and impervious throughout their thickness. Alternatively, the use of concrete curbs, or preformed curbs made of stainless steel or polyester concrete, minimise the risk of bacteria passing under an insulated panel wall.

Mechanical durability of a floor does not just come from the resin content but also from the size and quality of the aggregates used. Quartz or silica sands are relatively weak so the big stones in the floor should be harder minerals such as calcined flints, granite, basalt or bauxite, for example. Generally, the bigger these fillers are, the better the scratch and abrasion resistance. Larger and harder aggregates are also required to ensure the retention of slip resistance over the lifetime of the floor, particularly where textured floors are used in locations trafficked by hard plastic or steel wheels, such as meat bins, tray racks and mixing vessels, for example.

Chemical resistance

In the food and beverage industry a variety of chemicals will be encountered. In addition to cleaning chemicals which may affect the floor, it should also be borne in mind that organic acids, from the oxidation of vegetable oils and animal fats, lactic acid from milk, citric acid from fruit and acetic acid, will all degrade epoxy resin-based materials including resin grouts used in tiled floors. Phosphoric acid also attacks many epoxy resin-based materials.

The first impact of the substrate design and construction on the final floor is the presence, or not, of joints. The joint sealant will be weaker than the surrounding floor, it has poorer chemical resistance and is likely to have poorer hygiene characteristics. Joints are maintenance items, so must be visible for inspection and accessible for maintenance.

Joints should be positioned away from areas subject to chemical or high temperature discharges. They must be well detailed to protect the edges from mechanical damage caused by small hard plastic or steel wheels.

The best sealant for any joint will depend upon the amount of movement at the joint, the chemical resistance required, in service temperatures and the type of traffic. Harder sealants usually perform better where floors are trafficked by small hard wheels, while more flexible sealants can accommodate greater movement. In larger production halls, long channel drains can produce a fall pattern that is easier to build and use than a series of envelope falls and gullies.

In areas where there is likely to be high temperature spillages, steel reinforcement, including steel fibre reinforcement, should be at least 20mm below the surface of the substrate concrete, otherwise the differential movement between the steel and the concrete can lead to cracking. With good design almost all joints in the substrate concrete can be eliminated. Those few joints that are still necessary can be positioned in low risk and technical areas locations where they can be effectively inspected, cleaned and maintained with minimum disruption to production.

Never compromise

Compromising on good floor design to achieve initial savings can lead to ongoing maintenance costs long after the project is completed. It is always worth bearing in mind the cost of lost production in the event that the plant needs to close for floor refurbishment again in the future.

It should always be borne in mind that the most expensive floors are those that fail, leading to accidents and lost production and all the costs associated with managing the floor failure and the necessary repair works. Choose floor finishes that can demonstrate their longevity and do ensure that correct installation of the substrate concrete takes place.

It is equally important to ensure that the floor finish is correctly installed by a specialist applicator, that is familiar with the flooring system to be installed and can be relied upon to do the work in accordance with the manufacturer’s instructions and good site practice.