Article - August 21, 2017 By LarsonElectronics.com

Challenges and Solutions during Washdown in Industrial Processing Facilities

In order to maintain high sanitation standards, industrial processing facilities must conduct washdown sessions on a regular basis. This includes food processing plants, pharmaceutical facilities, meat storage buildings, dairy processing operations, commercial bakeries, institutional kitchens and industrial freezers.

Without the right equipment, washdown sessions can wreak havoc on machines and tools in the facility. Because of this, such units are required to be closely regulated and manufactured with superior materials and designs.

What Happens during a Washdown Session?

To better understand what type of equipment is needed to withstand washdown sessions in industrial processing facilities, it is important to first know what happens during one. Washdown is an integral part of food processing operations, which is scheduled routinely depending on the type of establishment and the products being handled in the facility.

This process targets production machinery, lights, floors, walls and other surfaces where bacteria (air or water based) may exist. The two major elements that make washdown sessions successful in removing bacteria are high-pressure water jets and cleaning agents. Focusing on the first element, high-pressure water jets are used to dislodge any particles and residue on the surface. In some facilities, water stream is mixed with pressurized steam for disinfection, causing the temperature of the jet to get very hot – sometimes exceeding 50°C. Though this is not ideal for meat processing plants, which utilizes cold pressurized water to avoid fog, the formation of water droplets and condensation. Operators typically spray targets from a distance of six to eight inches at a staggering rate of 1,000 gallons per minute. In a food processing facility, such targets include emulsifiers, mixers, tables and more.

Cleaning agents are applied to the surface to kill bacteria and remove filmy buildup. As one might expect, substances used during this stage are corrosive. The types of abrasive cleaners used are the following: self-foaming cleaners, acids, chlorine, caustic soda (sodium hydroxide) and more. These solutions are applied and must stay on the surface for a set amount of time (roughly 30 minutes). Corrosive cleaning agents that are not handled or mixed properly can damage equipment in the facility. In pure, dry form, sodium hydroxide typically takes on the shape and size of pellets. When used for cleaning, it is mixed with water. The exothermic chemical reaction causes a sudden release of heat. Direct contact with the mixture could result in burns (when exposed to skin) or warping and bursting (when exposed to unprotected or weak surfaces).

Selecting the Right Materials

For manufacturers, making equipment resilient to continuous washdown sessions starts with choosing materials that are capable of withstanding both high-pressure water jets and corrosive cleaning compounds. With this in mind, it’s no surprise that a preferred material in industrial food processing equipment and machinery is stainless steel. Specifically, Type 303, 304 and 316 stainless steel are capable of standing up to sodium hydroxide, at temperature thresholds below 95 °C. Type 316 stainless steel is recommended for both pharmaceutical and food processing operations, due to the presence of molybdenum for added resistance against pitting.

Materials that are not commonly used in industrial processing include aluminum, treated carbon steel and copper alloy. When aluminum is exposed to chlorine, the chemical reaction causes the formation of a white-like rust. Furthermore, from a long-term perspective, aluminum or cast iron coatings may separate, allowing harsh chemicals to build up in openings. Stainless steel is only applicable to sections of the facility that are directly targeted by operators during washdown sessions. Surfaces that are infrequently cleaned or targeted can be aluminum or cast iron (treated).

Unfortunately, some equipment is not ideal for using metal in construction. In some cases, high-strength, non-hygroscopic plastics, preferably variants that do not contain softeners or formaldehyde, may be used as a substitute in machines, like conveyor systems. For casings and lenses, glass is avoided at all costs. Instead, impact resistant acrylic or polycarbonate is used.

Challenges in Design

In addition to selecting the right material, industrial processing equipment must be designed to prevent the ingress of foreign contaminants, water, pressure, heat and chemicals. To reduce buildup, machines and electronics are usually designed to be dismantled quickly. For instance, tool-less ballast for lighting systems and one-piece components are preferred to streamline maintenance. Additionally, sloped covers and flanges are useful for directing water flow to the drainage system.

For floor mounting systems and table legs, short variants are more suitable for industrial processing to decrease the collection of bacteria. Smooth surfaces are preferred over rough finishes – also to make cleaning easier. Watertight plugs are installed at various access points of equipment to prevent unwanted ingress. O-rings are applied to improve sealing. Seals are one of the first components to succumb to high-pressure jets and cleaning chemicals. Fortunately, they are cheap to replace and maintain, compared to replacing the whole machine or its major parts.

Addressing Compliance and Industrial Regulations

Safety regulations and standards play active roles in conceptualizing, manufacturing, installing, using and maintaining industrial processing equipment. Adhering to such guidelines can greatly reduce the risk of contamination and failure during washdown sessions. The industrial processing sector is filled with regulations that make working in such environments safer and barrier-to-entry challenges more steep for equipment manufacturers.

For regulations related to food handling sanitation practices, OSHA standard 1910.141(h) is often cited. This guideline governs the way such facilities should be cleaned and disinfected.

Perhaps the most common marking in industrial processing equipment is NSF International. The not-for-profit, third-party institution requires equipment that comes in contact with food particles to meet the requirements of the FDA (Federal Food, Drug and Cosmetic Act). NSF certification breaks down compliance into three categories: Non-food Zone, Splash Zone and Food Zone. For food grade lighting systems, only the first two categories are applicable. The design and threshold of industrial processing luminaries must comply with NSF C-2 listings.

NEMA and IP ratings are essential markings and standards for industrial processing units. NEMA compliance ensures equipment and enclosures are capable of withstanding exposure to abrasive chemicals, dust, water and corrosion (depending on the level of rating). IP ratings are applied to streamline protection arising from the ingress of water from high-pressure jet and steam. Common IP ratings for industrial processing equipment include IP65, IP67 and IP9K. IP codes are classified accordingly in ANSI/IEC standard 60529.

Lastly, even lubrication in machines are regulated for food safety. Because such dense liquids can escape, when exposed to hot water and steam, where they can contaminate food and cause chemical reactions, businesses must carefully select and apply types that have been approved by industrial regulators. The FDA, under section 121.2553, and the USDA, with a USDA AA rating (e.g., USDA Class 2 grease), sets forth strict guidelines surrounding the use of machine lubrication.