Clean Steam System Design Fundamentals

Clean steam is saturated steam made from purified water that is used to sanitize equipment in cleanrooms, pharmaceutical manufacturing and processing facilities, and medical settings. It allows for non-contact cleaning of equipment, including corners and tight or enclosed spaces.

In addition to generating clean steam, the system must be designed to prevent internal corrosion both within the steam system and in the equipment being sanitized. Microbes and other contaminants also need to be prevented from entering the steam system and reaching equipment or products. Controlling contaminants prevents products from becoming tainted and increases the service life of equipment.

Here, we’ll look at how preventing contamination in a clean steam generation system keeps equipment sterile and maintains product quality and purity.

How a Clean Steam Generator Works to Prevent Corrosion

Avoiding corrosion is essential to the upkeep and operation of clean steam generation and processing equipment. Keeping particles of rust and other corrosion by-products out of equipment and manufactured products is critical to product quality and safety as well.

Standard utility steam used for industrial processes that don’t require sterile steam is generated with water heated in a boiler. The components in the system can be made with various metals, most of which can rust. As a result, the water is generally treated with anti-corrosion chemicals to prevent rust and other forms of corrosion in the steam generator system and in the equipment it feeds.

Unlike the water used for utility steam, there are no corrosion inhibitors in clean steam feedwater. In most cases, purified water or water filtered by reverse osmosis (RO) is used to create clean steam. For this reason, it is important to use materials that resist corrosion such as 316L stainless steel, titanium, and PTFE or EPDM polymer materials.

Even when 316L stainless steel is used, rouging corrosion can occur, in which the steel’s surface becomes covered with a red-brown film. While not problematic itself, this film can develop a powdery coating, which can detach and contaminate the steam. Periodic derouging removes the build-up.

Preventing Entry of Contaminants

Clean steam must always be free of contaminants at the point of use. These can include chemicals, rust or other particles from the corrosion process, bacteria, molds, and dirt or debris. Care must be taken to avoid common causes of contamination, including:

• Leaks in steam traps, hoses, or feedwater tanks
• Outside air that gets pulled into the system
• Standing condensation that permits bacterial growth
• Corrosion in tanks, heat exchangers, or other equipment
• Bacteria that grow through RO membranes and other surfaces can get into the system over time

Preventing Microbial Growth

Steam can kill bacteria and spores at typical operating pressures, and therefore components of a clean steam generation system that experience continuous exposure to steam will remain free from these contaminants. However, if condensate collects in the system and cools, the standing water can create an environment that permits bacterial growth.

Byproducts from the destruction and breakdown of bacteria, including endotoxins, remain in the system and cannot be destroyed by the steam. Endotoxins are often lipopolysaccharides from the cell walls of Gram-negative bacteria or pyrogens. They are a major concern in the manufacture and processing of injectable pharmaceutical products.

Standing condensation can be prevented by angling pipes and traps to collect any water that collects. Traps, piping, and tubing should also be checked for leaks or damage regularly.

Contact Electro-Steam for Clean Steam Generators

At Electro-Steam, we provide high-quality, electric-fired clean steam systems for pharmaceutical, medical, and cleanroom use. Our offerings include steam generators and steam sanitization systems and accessories for industrial process steam and food processing applications. Our experienced and knowledgeable team can also design a customized system to meet your requirements.

Contact us to learn more about how clean steam generators work or to request a quote for your application.