What Is Clean in Place (CIP)?

Clean in place (CIP) cleans the product-contact surfaces inside closed process equipment without dismantling it. Pumps circulate rinse water and cleaning chemicals through pipework, tanks, heat exchangers and fillers, and a controller checks that each step reached the right time, temperature, flow and concentration before the line is released back to production.

Before CIP, dairies and breweries took pipework apart by hand every day to clean it. Automating the job makes cleaning repeatable, shortens downtime, keeps staff away from hot caustic and acid, and produces a record that the line was cleaned properly. CIP is now standard in dairy, brewing, soft drinks, juice, sauces, pharmaceuticals and cosmetics, anywhere liquid or pumpable product runs through closed equipment.

Cycles vary by plant and product, but most follow the same pattern. The table shows a typical dairy-style cycle; the concentrations and temperatures are common starting points, and each plant validates its own.

Conductivity sensors confirm when one solution has been flushed out and the next has arrived. Flow in pipework is kept high enough for turbulent flow, commonly quoted as at least 1.5 m/s, because slower, smoother flow leaves a still layer of liquid against the pipe wall where soil survives. Return pumps and air blows clear each solution before the next, and tanks are cleaned by spray balls or rotating jet heads that wet every internal surface.

Cleaning engineers describe CIP with four factors, often called Sinner’s circle. Reduce one and another must increase to get the same result:

CIP sets fall into a few common designs. A single-use system makes up fresh solution for each clean and sends it to drain, which suits heavily soiled or sensitive processes. A recovery or reuse system stores caustic and acid in tanks, tops them up and reuses them across several cleans, saving water, chemicals and energy. Large sites often have a centralized CIP kitchen serving many circuits, while smaller plants and breweries may use a mobile CIP cart moved between vessels.

Two related terms often appear alongside CIP. Clean out of place (COP) means removing parts and cleaning them in a parts washer or tank. Sterilize in place (SIP) follows CIP in pharmaceutical and aseptic plants, typically using steam to sterilize the cleaned equipment. Open-plant washdown, by contrast, is the manual foam, rinse and sanitize of the outside of machines, floors and everything in the splash zone.

Hygienic design makes CIP possible: equipment must drain fully and have no dead legs or crevices where solution cannot reach. EHEDG publishes the main European guidance and a test method for in-place cleanability, which our guide to EHEDG explains.

Every CIP set is run from a PLC and an HMI that shows the cycle, records the verification data and alarms when a step fails. Many sites log each clean to a historian or MES so quality teams can release batches against it. The HMI sits outside the closed circuit, so CIP chemicals never reach it, but it is still foamed and hosed during open-plant washdown and is often splashed during hose connections and tank work.

That puts CIP panels in the same category as any other washdown HMI: a stainless steel housing, a flat sealed front, fanless cooling and sealed connectors. Our guide to hygienic design for washdown computers explains what that means for sealing and materials, and our IP69K panel PCs and stainless steel panel PCs are built for these areas.

We supply IP69K and stainless steel panel PCs for CIP and washdown areas with the connectors and mounting matched to the site, and integrate and test each system before it ships. Tell us how the area is cleaned and which control system runs it, and we will recommend the system to suit.