CIP Cleaning and Chemicals in Dairy Plants

CIP cleaning safety: where does the risk begin?

CIP (cleaning in place) is a system that cleans production equipment in place without dismantling it. In dairy plants, raw milk tanks, pasteurisers, yoghurt and ayran tanks, filling machines and the pipelines between them are cleaned this way after every production run. The system prepares cleaning solutions in its own tanks, sends them down the line with pumps and collects them back. Thanks to automation, cleaning is often started from a screen; this convenience also means that risks remain invisible from the point of view of CIP cleaning safety.

A typical CIP cycle and the main risk at each step are as follows:

Concentration and temperature values vary from plant to plant; make your own CIP recipe and your chemical supplier's safety data sheets the basis of the risk assessment. Dairy businesses around Karacabey and Mustafakemalpaşa in Bursa and beverage plants in the region are the on-site reality of this table.

Burn risk with caustic and acid CIP chemicals

Sodium hydroxide (caustic) solution, even when dilute, can cause serious and permanent damage if it gets into the eye; when hot, its effect on the skin is faster. Nitric acid is both corrosive and oxidising. Peracetic acid gives off irritating vapour. In caustic and acid CIP systems, most burns happen at three moments:

1. Transferring concentrated chemicals: Splashing during transfer from an IBC or drum to the dosing tank.
2. Opening a connection: Opening a union, seal or flexible hose connection while the line is under pressure or contains solution.
3. Sampling and checking: Taking open samples to measure the conductivity or concentration of the solution.

Incompatible mixtures are a separate hazard. Mixing acid with disinfectants containing hypochlorite can release toxic chlorine gas. Mixing concentrated caustic quickly with water generates heat and can cause splashing. Acid and caustic must be kept apart at dosing points and in storage. For separating incompatible chemicals, see our article on chemical storage compatibility.

PPE: For chemical transfer and connection work, chemical goggles together with a face shield, gloves made of the material recommended in section 8 of the SDS (safety data sheet), a chemical-resistant apron and boots are used. For how to read the SDS, see our article on how to read a safety data sheet.

Hot lines, pressure and hose connections

CIP lines are interwoven with product lines. In many plants, which tank is connected to cleaning and which to production is determined through flexible connection panels or valve clusters. In this arrangement, pay attention to the following:

• Pipe labelling: Label CIP supply and return lines with their contents and flow direction; it should be clear at a glance which line contains hot caustic.
• Seal and connection checks: Hot caustic wears out seals over time. A dripping connection is a warning of a connection that will spray when opened.
• Pressure and temperature checks: Before opening a connection, verify that the line has been drained, depressurised and has cooled down.
• Return pump: A blockage or air leak in the return line can cause solution to collect in the tank; an unexpected liquid level in the tank creates a risk for the next intervention.

Cleaning inside tanks and confined spaces

The purpose of CIP is to make entering the tank unnecessary; however, cleaning inside tanks is occasionally needed because of spray ball failure, internal inspection or stubborn soiling. A dairy tank, with its narrow entry, slippery inner surface and chemical residue, is a typical confined space. In beverage tanks related to fermentation or carbonation, carbon dioxide build-up should also be assessed.

Before entering the tank:

1. Issue a work permit; write down the entrant, the attendant and the rescue personnel.
2. Physically isolate the CIP supply: Remove or blank off with a blind flange the CIP line, product and steam lines coming to the tank; do not rely only on a closed valve.
3. Lock out agitators and pumps: Isolate and lock out motors, the air supply to pneumatic valves and steam valves.
4. Drain and rinse: Verify that no solution remains in the tank, that rinsing has been carried out and that the pH has been checked.
5. Test the atmosphere: Measure oxygen and, if necessary, other gases before entry and throughout the work.
6. Rescue plan: The attendant stays outside the tank; rescue equipment and communication are ready.

For details of preparation and measurement, see our articles on working in confined spaces and confined space gas testing.

CIP line lockout: do not trust the automation

The most dangerous CIP accident is the automation starting the cleaning programme while someone is inside a tank or a line is open. A "maintenance mode" on the screen or a valve that appears closed is not a physical lock. Set up the following arrangement for CIP line lockout:

• Energy list: Prepare an energy isolation list for each tank and line, including electricity, compressed air, steam and chemical supply points.
• Physical isolation: On chemical and steam lines, in addition to closing valves, prefer the method of removing the line, fitting a blind flange or disconnecting the flexible connection.
• Personal lock: Every worker carrying out an intervention fits their own lock to the isolation point and keeps the key with them.
• Pneumatic valves: Isolate and lock out the valve's air supply and verify the valve's position on site.
• Automation permission: The control room knows, through a written instruction, not to start the cleaning programme until the locks on site have been removed; at shift handover, open locks are handed over.
• Verification: After locking out, check that the energy has really been isolated by trying to start the pump locally.

For all the steps, see our article on LOTO lockout and tagout.

Dairy plant chemical delivery, dosing and storage

Bulk chemical delivery is an overlooked risk in dairy plants. Discharging acid into the caustic tank, or caustic into the acid tank, can cause a violent reaction. To prevent this:

• Distinguish filling points with the chemical's name and different connection types, and keep them locked.
• Carry out deliveries under the supervision of an authorised worker from the plant; compare the product name on the delivery note with the label on the filling point.
• Position tanks inside leak-tight bunds against overflow; keep a spill kit. For response, see our article on chemical spill response.

The Regulation on Health and Safety Measures for Work with Chemical Agents requires the employer to assess the risks arising from chemical agents and to take measures according to this assessment. Where workplace exposure measurement is needed, we plan the measurements with accredited laboratories and enter the results into the risk assessment.

At Bursa Sistemer, we treat CIP systems as a separate process in risk assessment work at food businesses in Bursa and the surrounding provinces, and monitor lockout and confined space practices on site as part of our OHS specialist service. For other risks in the sector, see our food sector page, and for biological risk in water systems, our article on legionella risk.

Frequently Asked Questions

What is the most common accident in CIP cleaning?

Caustic or acid solution splashing into the eyes and onto the skin during chemical transfer or when a line connection is opened. Draining the line, releasing the pressure and wearing a face shield and chemical goggles before opening the connection prevents most of these accidents.

Can caustic and acid be stored in the same place?

They should not be stored in the same spill bund or in a way that allows them to mix. Incompatible chemicals should be kept in separate bunds, labelled and with different filling connections; the risk of discharging into the wrong tank during delivery should be checked in particular.

Can a tank be entered while the CIP programme is running?

No. Before entering the tank, the CIP, product and steam supplies are physically isolated, agitators and pumps are locked out, the tank is drained and rinsed and the atmosphere is tested. Entry is made under a confined space work permit and with an attendant waiting outside.

Does selecting maintenance mode on the screen replace lockout?

It does not. A maintenance mode in the software or a valve that appears closed can change through an incorrect command or a fault. Lockout is achieved by physically isolating energy and chemicals and by each person carrying out the intervention fitting their own lock.