Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 12,5 % Cl | B | C | |
| 15 % | B | C | |
| dilute | B | C | |
| saturated | B | C |
Material comparison at 20 °C
Resistance overview
PP maintains a consistent rating of B across all 4 tested concentrations (12,5 % Cl, 15 %, dilute, saturated) of Sodium Hypochlorite (Bleach) at 20 °C. The fact that the rating does not change with concentration within the tested range simplifies material selection, though the boundary conditions beyond this range remain untested. However, at 50 °C the resistance rating drops, indicating that temperature must be factored into the design. For heated applications, additional testing under actual service conditions is strongly recommended.
Application context
Sodium Hypochlorite (Bleach) is commonly encountered in chemical processing and water disinfection. PP (Polypropylene) is a thermoplastic typically used for tanks, piping, containers and liners. Because Sodium Hypochlorite (Bleach) is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.
Practical recommendation
PP is suitable for use with Sodium Hypochlorite (Bleach) under normal conditions, but some minor effects on the material are expected over time. Periodic monitoring for swelling, softening, or weight change is recommended, especially for long-service components. Avoid prolonged exposure at elevated temperatures, as the resistance decreases further at 50 °C. For safety-critical or long-life applications, consider PMP, Polystyrene, Polysulfone instead, which are rated A for this chemical.
Did you know?
Polypropylene was first developed in the 1950s and remains one of the most widely used thermoplastics in chemical handling equipment.
Materials rated A or B at 20 °C
Based on the row for 15 %, 20 °C.
- Thermoplastics
- HDPE B, PVC Rigid A, LDPE B, Polycarbonate B, Polystyrene A, Polysulfone A, PMP A, SAN A
- Fluoropolymers
- PTFE A, FEP A, ECTFE/ETFE A
- Elastomers
- Viton (FPM) A
- Metals
- SS 316 B
About PP
Polypropylene resists most acids, alkalis and salt solutions. Concentrated oxidising acids, chlorinated solvents and aromatic hydrocarbons attack it, and it turns brittle below about 0 °C.
Rating scale
- A very good resistance
- B good resistance
- C limited resistance
- D not resistant
- – no data
- K no general statement possible
A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.
About this data
The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.
A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.