Group products by actual duty
Create a matrix of product, cleaning fluid, temperature, material approval, pack and required cleanliness.
Multi-product filling
One chemical filling line can handle several products only when the complete product path, cleaning method, operating range and line-clearance controls are suitable for every approved product. Products should be grouped by compatible duty, and any uncertainty should be resolved through component evidence and representative changeover trials rather than assumed from viscosity alone.
Direct answer
Start by listing every product and cleaning fluid that may contact the filler. Record formulation identity, concentration, density, viscosity and temperature range, foam, solids, vapour or flammability information, colour or odour carry-over concerns and the required residue limit before the next batch.
Then map the full path: source connection, hose, pump, meter, valves, filters, nozzles and any recirculation or return line. A common frame and conveyor do not require a common wetted path. Changeable dosing sets or dedicated hoses may provide flexibility without forcing incompatible products through the same components.

Approve the machine or process against the actual product, pack, operating range and site interfaces. Record assumptions and what must be confirmed by trial.
Decision table
| Approach | Useful when | Evidence to require |
|---|---|---|
| Shared fixed path | Product families have compatible materials, cleaning fluids and residue limits | Approved component schedule, retained-volume review, cleaning method and witnessed line-clearance test |
| Changeable contact set | Products need different hoses, pumps or nozzles but can share the machine frame and controls | Positive identification, connection control, storage, inspection and change-part reconciliation |
| Dedicated path or machine | Products react, residues cannot be verified, materials conflict or open cleaning creates excessive risk | Defined boundary, segregation, labelling and controls preventing the wrong path being selected |
Decision sequence
Create a matrix of product, cleaning fluid, temperature, material approval, pack and required cleanliness.
Identify low points, valve cavities, hoses, filters and return lines that can hold product.
State how cleanliness is checked: visual, rinse, analytical, conductivity, colour, mass balance or another site-approved method.
Run the hardest credible sequence, including stop time, draining, cleaning, inspection, restart and first acceptable packs.
Use identification, recipe permissions, line clearance and documentation proportionate to the consequence of an error.
Authoritative context
A shared-path decision must be part of the employer’s product, COSHH and—where relevant—DSEAR assessments. The current safety data sheet helps identify hazards but is not the complete workplace assessment. Review HSE safety data sheet guidance and HSE COSHH assessment guidance with competent site-specific input.
Avoidable errors
Buyer questions
A shared path is acceptable when every product and cleaning fluid has an approved component duty, the retained volume is understood, the clean endpoint can be verified, and the line can prevent the wrong product or setup being selected. The acceptance should cover the most difficult credible changeover, not only a water rinse.
A dedicated path is usually better when products react, material requirements conflict, carry-over limits are very low, residues cannot be measured reliably, or repeated dismantling would create excessive exposure or connection errors. A dedicated path can be a separate machine or a controlled removable dosing set.
Define what must be absent, where it could remain, how it is checked and who releases the line. Combine physical inspection with the site-approved test method and reconcile hoses, filters, nozzles, tools, labels, recipes and first-off packs before the next product is released.
Provide representative samples of each product family, every cleaning fluid, smallest and largest packs, closures and any products that are especially sticky, coloured, odorous, foamy, corrosive or prone to settling. Agree hazardous-sample handling and disposal before dispatch.
Speak to Lancing
Send the product matrix, cleaning method, changeover frequency, fill and pack ranges, contact-path evidence and the line-clearance standard your site needs to achieve.