Resources
November 26, 2018

Steam System Engineering – Steam System Meanings and Terminology

Steam System Engineering

My name is Kelly Paffel, technical manager for Inveno Engineering, LLC located in Tampa, Florida. We are international and domestic engineering firm focused on steam system optimization.  Today I want to talk about steam system optimization, types of steam and terminology. This is part three of a three part series and today we’ll talk about culinary steam, pure steam, and clean steam.

Types of steam and terminology, the first one we’ll talk about is culinary steam. Culinary steam is always referred when we make contact with a food product using steam. And there’s many applications that we use steam to make contact with food product. Accepted practices 3A-609-03, but there’s also corporate policies governing us how to prepare utility steam to make contact with food product. Or the other regulations or rules of any other governing organization.

Culinary steam typically contains no additives. Or if additives are added, they are FDA or USDA approved. The purpose of a chemical additive is to prevent corrosion within the steam system. Therefore, if we’re not adding additives, then we want to be very aware of the materials that we’re using in the steam system. Preferred material is always stainless steel.

Steam filter, we bring the utility steam to a filter which is shown here in this picture here. This is a steam filter. Excuse me. This filter here will filter the steam down to the requirements of the incorporation or FDA. The thing with this is we typically come to a five micron, so we filter everything to a five micron. This ensures that no corrosion or other contaminants entering the process or make contact with the food substance. We don’t want any contaminants making contact with the food. Corrosion materials will be present in utility steam lines because we use carbon steel and we have oxygen corrosion typically in the steam system, so oxygen corrosion will produce corrosion byproducts.

The filter is totally stainless steel. Note, after the steam filter, after this filter here, all components here need to be stainless steel and no carbon steel should be used.

The main benefit of culinary steam over using pure or clean steam it’s more economical to produce and provide to the process. Culinary filtration does require yearly or semi-yearly inspections. With a filter system that we need to inspect, do maintenance on this filter here at least yearly or semi-yearly, depending on the operation.

The next type of steam or terminology is pure and clean steam. This terminology is usually mixed between the two, pure and clean steam, without any definite difference between the two. Expressions pure steam and clean steam are used repeatedly, but is seldom clear whether these two expressions mean the same thing. Not simple to answer this question. Good manufacturing practices, GMPs, often use the term clean steam without any further explanation.

A general definition, pure or clean steam does not contain any additives and created by heating a specific purified water, not like a utility steam. This is a purified water through a specific steam generator, pure or clean steam generator, which is typically made of stainless steel, to produce a high quality steam that is free of any chemicals or additives. You cannot take utility steam and make a clean steam or pure steam. You have to have a specific steam generator using specific purified water to produce clean or pure steam.

The water source can be one of the following: purified water it’s called PW, highly purified water which is HPW, and water for injection, WFI. These are our water sources for our clean steam generator. Again, we can’t use utility steam to make pure or clean steam. We need purified water, highly purified water.

Most common steam specifications require condensate to satisfy WFI requirements for conductivity, total organic carbon, TOC, and endotoxins which is referred to as pure steam. Limits normally exclude viable microorganisms cannot survive in the steam system. When to use clean or pure steam is determined by GMPs. Now general rules applicable to the pharmaceutical manufacturing are detailed in the Code of Federal Regulations CFR Title 21, Part 211. In this presentation we’ll not get into it. They do not provide any specific recommendations regarding steam, but they do present general requirements for facility systems, equipment, operation needed to prevent contamination of a pharmaceutical product during manufacturing which goes back to using pure or clean steam.

Keep the following in mind. Steam from a conventional boiler or utility steam is unsuitable for pharmaceutical and medical application because it does contain boiler additives, rust, corrosion and other undesirable materials. Other uses of pure steam include autoclaves, sterilizers, humidification of air conditioning systems for ventilation of clean rooms. There is a multitude of applications for clean and pure steam. They also have a big application for clean and pure steam as SIP, steam in place systems. We utilize in a pharmaceutical or medical processing clean and pure steam all the time.

Pure steam is used in products that have strict endotoxin limitations. It is required for end products such as injectables, intravenous products. Specifications for clean steam may be based on the following PW specifications in so far as chemical composition which is TOC and conductivity. The systems are monitored continuous for these levels to ensure that we have highly purified steam going through the process.

Just a summary of what we presented, the question of the day and the question I have for all facilities is that what is your steam system thermal cycle efficiency? When we talk about steam systems, optimization, steam engineering, what is your steam system thermal cycle efficiency? It’s a very important benchmark in your steam and condensate system.

That concludes our three part series. Again, Inveno Engineering, LLC can help you out. Short term impact :steam system assessments, steam system engineering, steam balancing, steam system performance, or even steam system training. We’ve trained now over a hundred different subjects in steam. Long term impacts: system upgrades, process changes, improving reliability and safety of course is always there. Contact us here at the following email addresses or come to our website, and thank you for attending our three part series and have a great day.