When to Use Hygienic Design vs. Washdown

Both washdown and hygienic design are common terms used in the food and beverage industry, and are increasingly being used in the packaging industry. These terms are used in different scenarios and easily confused with each other. What exactly are the differences between them, and in what applications are each used?

Why are hygienic design and washdown needed?

The consumer, and more specifically, the health of the consumer is the core concern of the food and beverage industry. Contaminated food can pose a danger to life and limb. A product recall damages the image of a company, costs a lot of money and as a worst case scenario can lead to the complete closing of the company. To prevent such scenarios, a producers primary objective is to make sure that the food is safe and risk-free for the consumer.image 1

In food manufacturing and packaging plants, a differentiation is made between the food area (in direct contact with the product), the spray area (product-related) and the non-food area. The requirements of the machine components are different depending on which area they are in.

The Food Area

In the food area the food is unpacked, or partially unpacked, and particularly susceptible to contamination. All components and parts that may come in contact with the food must not adversely affect this, e.g. in terms of taste and tolerability.

The following needs to be considered to avoid contamination:

  • Hygiene in production
  • Use of food contact materials
  • Food-grade equipment in Hygienic Design

These requirements result in the need for components that follow the hygienic design rules. If the component supplier fulfills these rules, the machine manufacturer can use the components and the producer can use the machines without hesitation.

Hygienic Design

Many component suppliers offer different solutions for hygienic design and each supplier interprets the design differently. So what does hygienic design mean? What must be included and which certifications are the right ones?

  • The material used must be FoodContact Material (FCM). This means that the material is non-corrosive, non-absorbent and non-contaminating, disinfectable, pasteurisable and sterilizable.
  • Seals must be present to prevent the ingress of microorganisms.
  • The risk of part loss must be minimized.
  • Smooth surfaces with a radius of < 0.8 μm are permitted.
  • There must be no defects, folds, breaks, cracks, crevices, injection-molded seams, or joints, even with material transitions.
  • There must be no holes or depressions and no corners of 90°.
  • The minimum radius should be 3 mm.

Supporting institutions and related certifications

There are different institutions which confirm and verify the fulfillment of these rules. They also support the companies during the development process.

image2

EHEDG – The European Hygienic Engineering and Design Group offers machine builders and component suppliers the possibility to evaluate and certify their products according to Hygienic Design requirements.

image33A – 3-A Sanitary Standards, Inc. (3-A SSI) is an independent, non-profit corporation in the U.S. for the purpose of improving hygiene design in the food, beverage and pharmaceutical industries. The 3-A guidelines are intended for the design, manufacture and cleaning of the daily food           accessories used in handling, manufacturing and packaging of edible products with high hygiene requirements.

image4FDA – The Food and Drug Administration is a federal agency of the United States Department of Health and Human Services, one of the United States federal executive departments. Among other things, the FDA is responsible for food safety.

What does a hygienic design product look like?

Below is an example of a hygienic design product.

image5

  • Stainless steel housing VA 1.4404
  • Laser marking
  • Protection class IP69K (IEC 60529)
  • Active surface made of PEEK
  • EHEDG conform
  • FDA conform

Since the product contacting area is associated with high costs for the plant manufacturer and the operator, it’s beneficial to keep it as small as possible.

The Spray Area

In the spray area, there are different requirements than in the food area.
Depending on the type of food that is processed, a further distinction is made between dry and wet areas.

image6
Areas in the food and beverage production

Here we are talking about the washdown area. Washdown capable areas are designed for the special environmental conditions and the corresponding cleaning processes.

Washdown

Components which fulfill washdown requirements usually have the following features:

  • Cleaning agent/corrosion resistant materials (often even food compliant, but this is not a must)
  • High protection class (usually IP 67 and IP 69K)
  • Resistant to cleaning agents
image7
Photoelectric sensor for washdown requirements

Ecolab and Diversey are two well-known companies whose cleaning agents are used for appropriate tests:

Ecolab Inc. and Diversey Inc. are US based manufacturers of cleaning agents for the food and beverage industry. Both companies offer certification of equipment’s resistance to cleaning agents. These certificates are not prescribed by law and are frequently used in the segments as proof of stability.

The washdown component must also be easy and safe to clean. However, unlike the hygienic design, fixing holes, edges and threads are permitted here.

For basic information on IP69K see also this previous blog post.

To learn more about solutions for washdown and hygienic design click here.

 

IP Ratings and ECOLAB Basics

WashdownSensorsIntegrating sensors in washdown applications can be confusing when considering the various approvals.  So what do they all mean?  If a sensor is an IP69K rated sensor does that mean it will survive everything?  In the world of sensors there is IP54, IP67, IP68 and IP69 so if my sensor is IP69K that means it is the best right?  The short answer is no.  Let’s take a brief look at the differences.

IP ratings will generally have two digits with the first digit referring to the solid particle protection.  The second digit indicates the level of protection against the ingress of water.

Sensors rated for IP54 indicates they are dust protected, meaning that dust can get inside the sensor, however, it cannot be enough to interfere with the operation of the equipment –  this is designated by the 5.  The 4 indicates that the sensor withstands splashing water on the housing from any direction with no detrimental effect.  The test for the splashing of water lasts at least five minutes with a water volume of 2.64 gallons per minute with a pressure of 7.25 to 21.76 PSI.

IP67 rated sensors are the most commonly used sensors on the market.  Even most electrical enclosures used in automation are IP67 rated.  The 6 indicates these devices will not allow the entry of dust.  The 7 indicates that the sensor can be immersed in water to a depth of 1 meter for 30 minutes.

IP68 rated sensors are dust tight sensors that can be immersed in water continuously under conditions specified by the manufacturer.  Typically the depth of the immersion is 3 meters.

The IP69K rating is based on a dust tight sensor that can withstand high pressure sprays.  The devices are sprayed with a pressure of 1,160 to 1,450 PSI.  The water temperature can be as high as 176°F with a flow rate of 3.7 to 4.2 gallons per minute.  The distance from the nozzle to the device is 4 to 6 inches.  The sensor is placed on a rotary table that rotates at 5 revolutions per minute and the sensor is sprayed for 30 seconds at four angles 0°, 30°, 60°, and 90°.

The ultimate sensor would have a rating of IP67/IP68/IP69 indicating that it will survive submersion and high pressure washdown.  Also, some of these sensors are 316L stainless meaning they have low carbon content and are more corrosion resistant than other stainless steel grades.  Are all IP69K sensors stainless steel?  No, some sensors utilize polycarbonate-ABS thermoplastic.

Usually during washdown applications in the food and beverage industry the spray is not just water but some sort of cleaning chemical or disinfectant.  These aggressive cleaning and disinfecting agents can attack different housing materials.  This is addressed by the ECOLAB certification.

The ECOLAB test consists of testing the housing and sensor materials to exposure to these aggressive cleaning and disinfecting agents.  The devices are tested for 14 to 28 days at a room temperature of 68° F.  During this time the sensor is visually inspected for swelling, embrittlement, or changes in color.

Don’t forget that even though the sensor has the correct IP rating for your application that the mating connector has to meet the same specifications.  For example, if the sensor is IP69K rated and a IP67 mating cable is used then the lower IP rating has precedence.

If you are interested in what sensors and cables meet washdown requirements, please visit www.balluff.us.

The basics of IP69K Washdown explained

Ask 10 engineers working in Food & Beverage manufacturing what “washdown” means to them and you will probably get about 12 answers.  Ask them why they wash down equipment and a more consistent answer appears, everyone is concerned about making clean healthy food and they want to reduce areas of harborage for bacteria.  These environments tend to be cool & wet which usually leads the engineers to ask for 316L stainless steel & ingress protection of IP69K from component manufacturers and also ask for special component ratings.

So what are the basic elements of the washdown procedure?

  • Hot! – Minimum 140F to kill microbes & bacteria.
  • High Pressure! – Up to 1000psi to blast away soiled material.
  • Nasty! – Water, caustics, acid detergents, spray & foam everywhere.
  • Hard Work! – Typically includes a hand cleaning or scrubbing of key components.
  • Regular! – Typically 15-20hrs per week are spent cleaning equipment but in dairy & meat it can be more.

What requirements are put onto components exposed to washdown?

  • Stainless Steel resists corrosion and is polished to level the microscopic roughness that provides harborage for bacteria.
  • Special Component Ratings:
    • ECOLAB chemical testing for housings
    • FDA approved materials
    • 3A USA hygienic for US Equipment
    • EHEDG hygienic for European Equipment
  • IP69K is tested to be protected from high pressure steam cleaning per DIN40050 part 9; this is not guaranteed to be immersion rated (IP67) unless specifically identified.

If you are interested in what sensors, networking & RFID products are available for use in food and beverage manufacturing with a washdown environment, please visit www.balluff.us.

Defining IP Ratings and NEMA Ratings

Share

As I was preparing to write my blog entry, I was browsing my e-mail and came across an article in the October Issue of TIA Newsletter (Totally Integrated Automation) from Automation World, concerning IP Ratings.  I found the article , very informative as it broke down the different degrees of IP ratings, as well as some similarity and differences between IP ratings and NEMA ratings.  I only wish there was some information involving IP69K. 

This article, IP Ratings – What are they and what do they mean,  is a great starting point to learn about IP Ratings, I suggest you stop by and read it. 

For more information about IP67, check out The Secret of IP67 Protection.