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EN 580 DCMT Dichloromethane resistance testing at a specified temperature

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EN 580 — Plastics Piping Systems — Unplasticized PVC (PVC-U) Pipes — Test Method for the Resistance to Dichloromethane at a Specified Temperature (DCMT)

EN 580 specifies a solvent-resistance test (DCMT) for unplasticized poly(vinyl chloride) — PVC-U pipes, irrespective of their use. A chamfered pipe section is immersed in dichloromethane (DCM / CH₂Cl₂) at a specified temperature T for 30 minutes, then inspected visually for signs of attack. 


Test Principle

A prepared PVC‑U pipe specimen with a chamfered end is immersed in technical‑grade dichloromethane (DCM) at a specified temperature T ±0.5 °C for (30±1) min. The DCM surface is minimized and covered with a thick water layer to reduce evaporation and improve safety. After immersion, the specimen is held in the water layer to drip off DCM, then dried and inspected for attack (whitening, cracking, precipitation). Attack indicates insufficient gelation; no attack confirms good fusion quality. 

EN 580 DCMT Dichloromethane resistance testing at a specified temperature


Test Specimen Information:

Length: 160 mm, cut with ends perpendicular to the pipe axis.

Quantity: Typically 3 specimens (unless specified otherwise).

Chamfer angle (full wall thickness, cutting only—no grinding, no heating):

e < 8 mm: 10°

8 ≤ e < 16 mm: 20°

e ≥ 16 mm: 30°

Oversized pipes: Cut into longitudinal sections to fit the container; minimize the number of sections.


Testing Equipment Required for EN 580: 

Chamfering machine: For precision chamfering without heat buildup.

Container: Glass or stainless steel; small diameter to minimize DCM volume; fitted with an adjustable two‑level grating (immersion and drip positions); lid to limit evaporation.

Temperature control: Thermostatic control + refrigeration + stirring to maintain T ±0.5 °C.

Fume hood: With extraction system for toxic DCM vapor.

Refractometer: To monitor DCM quality (refractive index variation ≤ ±0.002). 


Immersion Conditions / Test Parameters

ParameterStipulation
ReagentDichloromethane, technical grade (trace CH₃Cl / CHCl₃ / CCl₄ ≤1% each; even ~5% total impurities → no significant effect)
DCM levelSufficient to fully immerse the chamfered zone
Water layer over DCMPreferably 250–300 mm, not < 20 mm — minimizes surface area, suppresses vapour, provides drip zone
Bath temperature TSet by referring standard; controlled to (T ± 0.5) °C; T ≥ ~12 °C practical minimum
Refractive index checkDCM refractive index must not vary by > ±0.002 from initial in service; in practice check every ~3 months at high throughput (~700–800 tests/month → ±0.0005 drift/3 months)
DCM level maintenanceTop up between tests as needed


Test Procedures of EN 580 Dichloromethane resistance test:

Prepare specimens: cut to 160 mm, chamfer one end per wall thickness.

Set up the bath: fill DCM, cover with water, stabilize at T ±0.5 °C.

Use tongs and gloves to place specimens with the chamfered zone fully in DCM.

Immerse for 30 ±1 min.

Raise the grating to the drip level; hold 10–15 min in water.

Remove and air‑dry at least 15 min in a ventilated area.

Inspect for attack: whitening, cracking, dissolution, or precipitate.

Record results as No attack (pass) or Attacked (fail); describe attack if required.


Industry Fields / Applications

SectorContext
PVC-U pipe manufacturingPrimary users — DCMT is a batch-release QC test run daily/hourly on extrusion lines
Water supply & irrigation (potable / raw water pressure pipe)Verifies gelation before pipe is put into pressurized service where failure = leak / burst
Building drainage & vent (soil, waste, rainwater)Ensures consistent compound & extrusion — poor gelation shows up as brittle failure or solvent sensitivity at joints
Underground sewer & gravity drainageChecks that regrind levels, additive packages, and barrel/parallel head temperatures are in spec
Conduit & duct (electrical/telecom)Confirms material integrity for impact/toughness indirectly
Third-party certification (KIWA, WRAS, DVGW, AFNOR, etc.)DCMT is a routine audit/test-item for PVC-U pipe product certification in Europe


Related Standard: 

ISO 9852Unplasticized poly(vinyl chloride) (PVC-U) pipes — Dichloromethane resistance at specified temperature (DCMT) — Test method
EN 580Plastics piping systems - Unplasticized poly(vinyl chloride) (PVC-U) pipes - Test method for the resistance to dichloromethane at a specified temperature (DCMT)
GB/T 13526Unplasticized polyvinyl chloride(PVC-U) pipes dichloromethane resistance test method
EN 1452
PVC-U pipes for water supply. 


Related products and device

EN 580 Dichloromethane resistance tester

Methylene chloride tester/Dichloromethane soak testing machine is used to determine the resistance of unplasticised polyvinyl chloride (PVC-U) pipes to dichloromethane (methylene chloride) at a specified temperature (DCMT).

Related Standard

ISO 9852 Methylene chloride soak test, Dichloromethane resistance test

ISO 9852 specifies a method for determining the resistance of unplasticized poly(vinyl chloride) (PVC-U) pipes to dichloromethane at a specified temperature (DCMT). It is applicable to all PVC-U pipes, irrespective of their intended use.

Scope of application: Suitable for any homogeneous flat-walled, unplasticized PVC pipe, regardless of its intended use, It can be used as a means of rapid quality control in the production process. It is especially suitable for quality inspection and performance evaluation of PVC-U pipes. 


Core test principles

The ISO 9852 standard specifies a method for determining the resistance of PVC-U pipes to methylene chloride at specified temperatures (DCMT). This method evaluates the plasticization uniformity and internal structural integrity of the pipe specimen by immersing the pipe specimen in methylene chloride solution and observing the degree of damage to the surface of the pipe after impregnation.


FAQs: EN 580 – PVC‑U Pipe DCMT Test

Q1: What exactly does EN 580 describe?

A: EN 580:2003 is the European method standard that defines the DCMT test: how to prepare a PVC‑U pipe sample, expose it to dichloromethane (DCM/CH₂Cl₂) at a specified temperature T, and judge whether the material is attacked or not.

It does not by itself say what temperature is “pass” or “fail”—that comes from the referring product/standard (pressure pipe spec, drainage pipe spec, etc.).


Q2: Why test PVC‑U with a solvent at all? Isn’t this about chemical resistance?

A: Not really servicechemical resistance. The point is gelation/homogeneity quality from extrusion:

PVC‑U isn’t chemically cross‑linked. Its strength depends on fusion (gelation) of PVC particles during extrusion.

If gelation is poor, particle boundaries and micro‑voids remain weak. Those spots absorb/penetrate DCM, showing whitening, swelling, pitting or loss of material.

Well‑gelled PVC‑U resists DCM and shows no attack.

So DCMT is a rapid proxy for a hidden quality attribute that strongly influences mechanical behavior and long‑term performance.


Q3: Why not just rely on tensile/impact/dimensions?

A: Dimensions and even short‑term tensile can look fine while gelation is borderline. DCMT is surface‑ and boundary‑sensitive, and it’s fast (~1 hour). Think of it as a process health monitor, not a design‑property test.


Q4: Can I use EN 580 on plasticized PVC (PVC‑P), CPVC, PVCC, or fittings?

A: Officially: PVC‑U pipes only.

PVC‑P (plasticized) reacts very differently because of plasticizer.

CPVC has different solubility/resistance characteristics.

For fittings, the standard doesn’t define a generic fitting method; many specs only apply DCMT to pipe (wall thickness exceeding a minimum set by the referring standard). 


Q5: If EN 580 is the method, who decides the temperature?

A: The referring standard does:

EN 1452 family (PVC‑U pressure pipes for water) often references DCMT and sets the required T (commonly something like 15 °C or 20 °C depending on class/country adoption).

EN 1401 / EN 1329 (drainage/sewer) may reference DCMT as a quality check.

ISO 9852:2007 is the ISO counterpart aligned/realigned to EN 580:2003 (same essential method, same chamfer angles, same water‑layer vapour‑barrier logic).


Q6: Why is water placed above dichloromethane?

A: To reduce DCM evaporation by more than 90%, improve operator safety, lower chemical cost, and stabilize temperature.


Q7: Can I touch the specimen with bare hands?

A: No. DCM is toxic by skin contact; always use tongs and protective gloves.


Q8: How to check if DCM is still valid?

A: Check its refractive index. The variation must not exceed ± 0.002 from the initial value.





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