Clean-in-Place (CIP) and Sterilize-in-Place (SIP) are critical requirements for hygienic positive displacement (PD) pumps in food, beverage, and pharmaceutical processing. Proper CIP/SIP design ensures product safety, regulatory compliance, and equipment longevity. This guide covers CIP/SIP compliance for PD pumps.
CIP Fundamentals
What is CIP?
- Clean-in-Place: cleaning equipment without disassembly, using circulating cleaning solutions
- Removes product residue, soil, and bacteria from internal surfaces
- Typical cycle: pre-rinse → caustic wash → rinse → acid wash → final rinse → sanitize
- CIP is standard for food, dairy, beverage, and pharmaceutical processing
- Regulatory: 3-A, EHEDG, FDA, USDA, PMO (dairy), cGMP (pharma)
CIP Cycle Parameters
| Step | Solution | Concentration | Temp | Time |
|---|---|---|---|---|
| Pre-rinse | Water | — | 40-50°C | 5-10 min |
| Caustic wash | NaOH | 1-2% | 70-85°C | 15-30 min |
| Rinse | Water | — | Ambient | 5-10 min |
| Acid wash | HNO₃ or H₃PO₄ | 1-2% | 50-65°C | 15-20 min |
| Final rinse | Potable water | — | Ambient | 10-15 min |
| Sanitize | Hot water or PAA | — | 85°C or 200 ppm | 5-15 min |
SIP Fundamentals
What is SIP?
- Sterilize-in-Place: sterilizing equipment using steam, without disassembly
- Kills all microorganisms (including spores) using saturated steam
- Typical: 121-140°C, 2-4 bar, 15-30 minutes
- Used for: sterile products (UHT milk, sterile cream, biotech, pharma)
- More rigorous than CIP — requires steam-rated equipment
SIP Parameters
| Parameter | Standard | High-Level |
|---|---|---|
| Temperature | 121°C (250°F) | 135-140°C |
| Pressure | 2 bar (30 psi) | 3-4 bar |
| Hold time | 15-30 min | 30-60 min |
| Steam quality | Saturated, >95% dry | Clean steam (filtered) |
| Cool down | Natural or forced | Controlled rate |
CIP/SIP Design Requirements for PD Pumps
Drainability
- Pump must fully drain — no product or CIP liquid traps
- Pump casing: sloped drain, no horizontal dead legs
- Inlet/outlet: self-draining orientation (outlet at highest point)
- Seal chamber: drainable, no trapped liquid
- Verify drainability by visual inspection or dye test
- EHEDG and 3-A require full drainability
No Dead Legs
- Dead leg: pipe branch where liquid can stagnate (L/D > 2)
- Dead legs harbor bacteria, are not cleaned by CIP
- Pump design: no unused ports, no blind flanges, no long branches
- Instrument ports: use zero-dead-leg (ZDL) valves or sensors
- Seal flush connections: must be self-draining
- Verify with CIP coverage study (dye or riboflavin test)
Flow Velocity
- CIP flow must achieve turbulent flow (Re > 4000) for effective cleaning
- Minimum velocity: 1.5 m/s in piping, 2-3 m/s in pump
- PD pumps: run at CIP speed (may differ from product speed)
- Twin screw pumps: can pump both product and CIP at same speed (unique advantage)
- Verify CIP flow rate with pump supplier
Material Compatibility
- Wetted parts: 316L stainless (standard), 2205 duplex (high chloride)
- Elastomers: must withstand CIP chemicals and temperature
- EPDM: excellent for CIP (caustic/acid), up to 150°C
- Viton: good for CIP, up to 200°C (but limited in hot caustic)
- Silicone: poor for CIP (steam hydrolysis), avoid
- PTFE: excellent for CIP, up to 260°C
- FFKM (Kalrez): best for extreme CIP/SIP, up to 300°C
- Seal faces: SiC (excellent CIP resistance), carbon (OK but may wear)
- Verify all wetted materials with CIP chemical supplier
Temperature Rating
- CIP: 70-90°C (most pumps handle easily)
- SIP: 121-140°C (requires SIP-rated pump)
- Key components affected by high temp:
- Elastomers: must be rated for SIP temp (Viton, FFKM, PTFE)
- Seal faces: thermal shock resistance (SiC better than carbon)
- Bearings: may need cooling or high-temp grease
- Stator (single screw): many elastomers limited to 80-100°C
- Hose (peristaltic): limited temp range (EPDM up to 120°C)
- Thermal cycling: repeated heating/cooling can fatigue materials
- Preheat/cool slowly to prevent thermal shock
Seal Design for CIP/SIP
- Single mechanical seal: CIP compatible (verify elastomer), SIP may be limited (elastomer)
- Double mechanical seal: Best for CIP/SIP — barrier fluid protects seal from chemicals and temp
- Cartridge seal: Easy replacement, consistent installation, recommended
- Metal bellows seal: No elastomer in product, good for SIP (high temp)
- Magnetic drive: No dynamic seal, excellent CIP/SIP (but limited to magnetic drive pumps, not PD)
- Barrier fluid for double seals: clean water or glycol, pressurized above product
- Seal flush: Plan 32 (clean water flush) for abrasive products, Plan 23 (recirculation cooler) for hot products
CIP/SIP by Pump Type
Rotary Lobe Pumps
- CIP: fully capable, run at CIP speed (typically higher than product speed)
- SIP: capable with SIP-rated elastomers (Viton, FFKM) and double seal
- Advantages: large passages, good CIP coverage, drainable
- Considerations:
- CIP flow rate: verify with supplier (may need larger pump for CIP)
- Lobe clearance: CIP may affect clearance over time
- Front cover: must be drainable, no dead legs
- 3-A certified designs available
Twin Screw Pumps
- CIP: excellent — can pump both product and CIP fluids at same speed (unique)
- SIP: capable with SIP-rated elastomers
- Advantages:
- One pump for product + CIP (no separate CIP pump needed)
- Wide viscosity range (CIP fluids are low viscosity, product is high viscosity)
- Good CIP coverage, drainable
- Considerations: higher cost, larger footprint
- Best for: facilities wanting to simplify CIP system
Single Screw (Progressive Cavity) Pumps
- CIP: possible but limited — stator material may restrict temp/chemicals
- SIP: generally NOT recommended — stator elastomers cannot withstand 121°C steam repeatedly
- Considerations:
- Stator: EPDM up to 80°C, Viton up to 120°C (but CIP at 80°C may age quickly)
- CIP flow: may be limited (stator expands, reduces flow)
- Connecting rod/U-joint: may have crevices (hard to clean)
- Some designs: open stator (removable) for manual cleaning
- For SIP: use peristaltic or lobe pump instead
- For CIP: verify stator compatibility, use lower temp if needed
Gear Pumps
- CIP: possible but limited — tight clearances can trap product
- SIP: capable with SIP-rated seals and materials
- Considerations:
- Tight clearances: CIP flow may be restricted
- Gear mesh: can trap product, requires good CIP coverage
- Seal: double seal recommended for CIP/SIP
- Best for: clean, low-solids products (oil, syrup)
- Not recommended for: products with solids, fibers, or heavy residue
Peristaltic Hose Pumps
- CIP: possible but hose must withstand CIP chemicals
- SIP: limited — hose materials generally not SIP-rated
- Considerations:
- Hose: EPDM (good CIP), Viton (oil/fat), natural rubber (abrasive)
- Hose interior: may need manual cleaning or replacement
- No seals or valves — only hose is wetted part
- Single-use hose option for sterile applications
- Best for: abrasive, shear-sensitive, or sterile (single-use) products
- For SIP: use single-use hose or autoclave separately
Diaphragm Metering Pumps
- CIP: possible — diaphragm and valves must be CIP-compatible
- SIP: possible with SIP-rated diaphragm and valves
- Considerations:
- Diaphragm: PTFE (excellent CIP/SIP), EPDM (good CIP)
- Valves: ball/check valves, must be self-draining
- Low flow: CIP coverage may be limited (small passages)
- May need manual cleaning or flushing
- Best for: additive dosing, chemical injection
CIP/SIP Verification
Riboflavin Test
- Coat internal surfaces with riboflavin (vitamin B2) solution
- Run CIP cycle
- Inspect under UV light — any remaining riboflavin glows yellow
- Identifies dead legs, low-flow areas, poor coverage
- Required for: new installations, major modifications, regulatory audits
- Standard: ASTM E2059 or company SOP
ATP Testing
- Adenosine Triphosphate (ATP) test: measures biological residue
- Swab surfaces after CIP, measure ATP (relative light units)
- Pass/fail: < 10 RLU (strict), < 100 RLU (general)
- Quick, easy, but only measures biological residue (not chemical)
- Use for routine CIP verification
Microbial Testing
- Swab or rinse sample after CIP/SIP
- Test for: total plate count, coliforms, spores (for SIP)
- SIP validation: biological indicators (Geobacillus stearothermophilus spores)
- Required for: pharma, sterile products, regulatory compliance
- Frequency: routine (weekly/monthly), validation (quarterly/annually)
Temperature Mapping
- For SIP: verify temperature reaches 121°C at all points
- Use temperature data loggers or thermocouples
- Cold spots: identify and address (insulate, increase steam flow)
- Document for regulatory compliance
Common CIP/SIP Issues
- Poor CIP coverage: Dead legs, low flow, poor design. Use riboflavin test, redesign.
- Elastomer failure: CIP/SIP chemicals/temp degrade elastomers. Verify compatibility, use double seal.
- Stator damage (single screw): CIP temp/chemicals degrade stator. Use lower temp, verify material.
- Seal leakage after CIP: Thermal shock or chemical attack. Use double seal, preheat/cool slowly.
- Bacteria in dead legs: Product residue in stagnant areas. Eliminate dead legs, improve CIP flow.
- SIP cold spots: Inadequate steam, poor drainage. Insulate, increase steam, verify temp.
- Hose failure (peristaltic): CIP chemicals degrade hose. Verify material, replace regularly.
- Product residue after CIP: Insufficient time/temp/concentration. Increase CIP parameters, inspect.
Procurement Recommendations
- Provide: CIP/SIP cycle details (chemicals, concentration, temp, time, flow rate)
- Specify 316L stainless, Ra < 0.8 μm, fully drainable design
- Require 3-A and/or EHEDG certification
- For CIP: specify EPDM or Viton elastomers (verify compatibility)
- For SIP: specify Viton or FFKM elastomers, double mechanical seal
- For twin screw: verify CIP capability (one pump for product + CIP)
- For single screw: verify stator CIP temp rating (may be limited)
- For peristaltic: specify hose material per CIP chemicals
- Require CIP flow rate and pressure data from supplier
- Include riboflavin test or CIP coverage study in FAT
- Specify zero-dead-leg design for all ports and instruments
- For pharma/sterile: require SIP validation, temperature mapping
- Include spare elastomers and seals (CIP/SIP accelerates wear)
- Require CIP/SIP compatibility statement from supplier
Related Industries
CIP/SIP principles apply to pharmaceutical (cGMP, sterile), biotech (fermentation, cell culture), food (dairy, beverage, meat), and cosmetics (creams, lotions). The core principle — hygienic design with full drainability, no dead legs, material compatibility, and verified cleaning coverage — is consistent across all hygienic processing industries.