HFE-7100 (Novec 7100) Storage & Tank Compatibility

Storing HFE-7100 (Novec 7100)? Start Here

HFE-7100, marketed as Novec 7100, is a hydrofluoroether engineered fluid — principally methoxy-nonafluorobutane (C₄F₉OCH₃) supplied at ≥99.5% purity as a mixture of two structural isomers. It is a clear, colorless, low-odor, non-flammable liquid with a boiling point near 61 °C and a density around 1.5 g/cm³. Developed as a low-ozone-depletion, low-global-warming replacement for CFCs and HCFCs, it is used for precision and vapor-degreasing cleaning, particulate and flux removal, drying after aqueous or alcohol wash, lubricant/coating carrier-solvent deposition, and as a dielectric heat-transfer fluid in electronics, semiconductor, aerospace and data-center immersion cooling. Materials of construction (MOC) matter here less for chemical aggression — the fluid is mild — and more for containment: its low surface tension and volatility mean a tank that is chemically fine can still lose product to permeation, seepage and evaporation if not vapor-tight.

Is HFE-7100 Safe to Store in Polyethylene (HDPE / XLPE) Tanks?

Chemically, yes — rated S. Hydrofluoroethers do not swell, soften or dissolve polyethylene; HFE-7100 is documented as compatible with metals, glass and most hard polymers, including polyethylene and polypropylene. There is no acid, oxidizer or aromatic-solvent attack mechanism that degrades the poly resin. The caveat is operational, not chemical. With a boiling point of roughly 61 °C, high vapor pressure and very low surface tension, the neat fluid evaporates readily and can permeate or seep through fittings and seams. For a high-value engineered fluid, that means a polyethylene tank is materially safe but may not be the best retention choice: vapor-tight stainless or sealed lined-metal vessels with low-permeation, low-extractable elastomer seals are preferred for bulk holding. For short-term holding, transfer, or process-side day tanks where the vessel is sealed, HDPE/XLPE is appropriate. Always confirm against the current SDS and your specific blend (some products azeotrope HFE with trans-1,2-dichloroethylene, which changes the picture).

Material compatibility at a glance

HFE-7100 is chemically benign toward polyethylene, polypropylene, metals and glass. The governing storage concern is not chemical attack but its high volatility (boiling point near 61 °C) and very low surface tension, which drive evaporative loss and seam seepage. Polyethylene (HDPE/XLPE) is materially SUITABLE for the fluid; for retention of this costly, volatile engineered liquid, vapor-tight metal or sealed lined vessels are operationally preferred.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Vapor displacement / asphyxiation: heavy vapors are denser than air and can accumulate in low or confined spaces — ventilate and monitor oxygen before entry.
• Thermal decomposition: at flame or very high temperature the fluid can break down to hydrogen fluoride (HF) and perfluoroisobutylene (PFIB), which are highly toxic — keep away from open flame, welding and hot surfaces.
• Non-flammable but volatile: no flash point, yet high vapor pressure means rapid evaporative loss and pressure build in sealed warm containers — allow for venting/expansion.
• Defatting / drying: repeated or prolonged skin contact can dry and irritate skin; use nitrile gloves and avoid immersion.
• Eye / inhalation: avoid breathing high vapor concentrations; provide local exhaust for degreasing and immersion operations.
• Confirm per SDS: hazard profile is blend-dependent — azeotropes with trans-1,2-dichloroethylene carry added flammability and toxicity classifications.

Common questions

Can I store HFE-7100 in an HDPE or poly tank?

Chemically yes — HFEs do not attack polyethylene, so HDPE/XLPE is rated suitable (S). The practical issue is the fluid’s volatility and low surface tension, which cause evaporative loss and seepage. Use vapor-tight closures, and for long-term bulk storage of this costly fluid consider sealed metal or lined vessels.

Is HFE-7100 flammable?

No. It has no closed-cup flash point and is classified non-flammable. However, at flame or extreme heat it can thermally decompose into hydrogen fluoride and perfluoroisobutylene, so it must still be kept away from ignition and hot surfaces. Note that some HFE blends azeotroped with trans-1,2-dichloroethylene ARE flammable — check your SDS.

Why does the neat fluid carry no GHS pictograms?

The neat Novec 7100 fluid is generally not classified as hazardous under GHS, so it typically carries no signal word or pictograms. This reflects its low acute toxicity and non-flammability. Always verify against the specific supplier SDS, since custom blends and azeotropes can be classified.

What materials are NOT ideal for HFE-7100?

Fluorinated polymers and elastomers (PTFE, FEP, fluoroelastomers) absorb HFEs and swell over long exposure, so they are poor choices for permanent seals or linings. Standard nitrile/EPDM seals are usually serviceable but should be low-extractable-plasticizer grades. Metals, glass, HDPE and PP are fine.