Stainless Steel – Are you using the correct grade in your cleanroom?
What grade of stainless steel should you be using in a sterile environment?
Stainless steel cleanroom furniture obviously needs to be disinfected effectivley to reduce cleanroom contamination. However consideration also needs to be given to corrosion resistance, particularly with the use of some harsh cleanroom disinfectants and biocides.
Stainless steel is naturally protected from corrosion by a thin layer of chromium oxide. Oxygen from the atmosphere combines with the chromium in the stainless steel to form this passive chromium oxide film that protects it from further corrosion. Any contamination of the surface by dirt, or other materials, hinders that passivation process and traps corrosive agents, reducing corrosion protection.
What is the difference between grades?
Grade 430 is a ferritic, straight chromium, non-hardenable grade, combining good corrosion resistance and formability characteristics with useful mechanical properties. Its ability to resist nitric acid attack permits its use in specific chemicals applications but automotive trim and appliance components its largest fields of application.
These properties for 430 are specified for flat rolled product (plat, sheet and coils) is ASTM A240/A240M.
The typical application for 430 grade stainless steel includes:
- Lining for dish washer
- Refrigerator cabinet panel
- Automotive Trim
- Lashing Wire
- Element supports
- Strove Trim Rings
- Chimney Liners
Type 304 is the most versatile and widely used. It is still sometimes referred to by its old name 18/8 which is derived from the nominal composition of type 304 being 18% chromium and 8% nickel. Type 304 is an austenist grade that can be severely deep drawn. This property has resulted in 304 being the dominant grade used in applications like sinks and saucepans.
The typical applications for grade 304 would be:
- Sinks and Splashbacks
- Cutlery and Flatware
- Sanitary ware and throughs
- Brewery, Dairy, Food and Pharmaceutical production equipment
- Springs, Nuts, Bolts and Screws
Grade 316 is an austenitic grade second only to 304 in importance. 316 grade contains an addition of molybdenum that gives it improved corrosion resistance. This is particularly apparent for putting and crevice corrosion in chloride environments. Type 316 can withstand corrosive attack by sodium and calcium brines, hypochlorite solutions, phosphoric acid, and the sulfite and sulphurous acid.
Since type 316 stainless steel has a high corrosive resistance the typical use is more medical based. For example, grade 316 stainless steel is used for:
- Chemical and petrochemical equipment
- Pharmaceutical cleanrooms
- Laboratory benches and equipment
- Chemical transport containers
- Medical implants
What grade of stainless steel is best for cleanroom use:
As you are in a cleanroom or sterile environment you’ll be working with and around chemicals. So you would need a work bench which can withstand a chemical spill. 316 grade stainless steel is more expensive than the other grades but it has a high resistance to harsh chemicals. Since type 316 stainless steel has a high corrosive resistance, it is commonly used in the pharmaceutical and medical industry.
Here at Cleanroom Supplies we understand what it is like when all the standard cleanroom furniture catalogues you are looking through are, well…, too standard, and not quite what you are looking for. This exercise can be frustrating and time consuming. Cleanroom supplies stock standards stainless steel trolleys and stainless steel furniture.
We also fully understand the importance of good design and quality manufacture when dealing with controlled environments. That understanding comes from our Managing Directors experience in the design and construction of many cleanrooms and laboratory environments.
We will work with you and design the furniture you want – and best of all this service is Free! We will produce CAD drawings of your requirements. When you are happy with the design we will manufacture and deliver the furniture or bespoke fabrication for you.
This includes manufacture of items from 304 or 316 Grade Stainless steel, Trespa, laminates or any other cleanroom suitable material.
Click Here for more information on this check out our video on How Stainless Is Stainless Steel.