Poly naphthalene sulfonate (PNS) is another name for sodium naphthalene formaldehyde (SNF): sodium naphthalene sulfonate formaldehyde condensate, used as a concrete superplasticizer and dispersant. The chemistry is explained on polynaphthalene sulfonate (PNS); this page is for buyers: how PNS grades differ, what to put in a specification and how to qualify a supplier.
PNS Grades
PNS powders are sold by maximum sodium sulfate content. Our current grades:
| Grade | Sodium sulfate (Na2SO4) | Chloride (Cl–) | Cement paste fluidity | Solids | pH |
|---|---|---|---|---|---|
| SNF-5 (GAC-SNF-5) | 5% max | 0.4% max | 220 mm min | 91% min | 7 – 9 |
| SNF-10 (GAC-SNF-10) | 10% max | 0.4% max | 220 mm min | 91% min | 7 – 9 |
| SNF-18 (GAC-SNF-18) | 18% max | 0.5% max | 210 mm min | 91% min | 7 – 9 |
| SNF-20 (GAC-SNF-20) | 20% max | 0.5% max | 210 mm min | 91% min | 7 – 9 |
| Powder Grade, high solids (GAC-SNF-P) | 10% max | Below 200 ppm | Not listed | 95% min | 6.5 – 8.5 (1:10) |
What to Put in a PNS Specification
| Item | Why it matters |
|---|---|
| Sodium sulfate, max | Sets the grade; matters for liquid admixtures and active content |
| Chloride, max | Limits on chloride apply in reinforced concrete |
| Solids, min | Active product per kg |
| Cement paste fluidity and method | The basic performance check |
| pH | Consistency between batches |
| Water reduction in concrete, and standard used | Performance in a defined concrete test |
| Packaging and shelf life | 25 kg bags or 500–600 kg jumbo bags; typically 12 months |
Qualifying a PNS Supplier
- Get the TDS and SDS for the exact grade, and a recent batch COA.
- Check the CAS number and chemical name on the SDS; our superplasticizer grades use CAS 36290-04-7.
- Test a sample in cement paste and in your concrete against your current product.
- Agree acceptance limits and test methods in the contract.
- Keep a retained sample from each delivery.
Starting Dose
The current TDS gives a supplier-recommended starting trial range of 0.5–1.0% powder by weight of cementitious material, with 0.75% as the first trial point. Confirm the working dose by trial mixes with your own cement, aggregates and admixtures.
Documents and Quotations
- SNF-5 TDS (PDF)
- SNF-18 TDS (PDF)
- SNF-20 TDS (PDF)
- Grade selection, samples and quotations: SNF superplasticizer product page
Frequently Asked Questions
What is poly naphthalene sulfonate?
Poly naphthalene sulfonate (PNS) is sodium naphthalene sulfonate formaldehyde condensate, the same product as SNF. It is used as a concrete superplasticizer and dispersant.
Is PNS the same as SNF?
Yes. PNS, SNF and NSF are names for the same condensate. Grades differ mainly in sodium sulfate content.
What does PNS mean in construction?
In construction, PNS means poly naphthalene sulfonate, a naphthalene-based superplasticizer (high-range water reducer) for concrete.
What should a PNS specification include?
Sodium sulfate, chloride, solids, cement paste fluidity with its method, pH, and concrete water reduction with the standard used.
