Corrosion Inhibitors

Reducing fuel system damage

The internal corrosion of fuel storage and distribution systems can cause a variety of problems in both ground and aviation fuel applications.

These issues include:

  • Storage vessel and pipeline leakage
  • Contamination of fuel with particulates
  • Blockage of filters and screens from corrosion material
  • The requirement for expensive maintenance

Approved corrosion inhibitor additives are designed to protect against these problems. Innospec produces class-leading corrosion inhibitors for use in storage, pipeline and aviation applications.

Our corrosion inhibitors impart anti-rust properties to fuels and provide excellent corrosion protection to fuel distribution systems.

The inhibitors are surface-active ‘polar’ molecules, which attach themselves to metal surfaces. Once attached, the molecule’s oil-soluble tail forms a water repellent layer over the metal.

Protecting pipelines

Corrosion is the main cause of pipeline leaks, an issue which creates millions of dollars worth of damage every year. Where they occur, pipeline leaks can have substantial cost implications on refiners and operators, in terms of clean-up and remediation requirements.

Corrosion inhibitor additives prevent corrosion damage to the fuel storage and distribution system. They are particularly effective in protecting the pipeline hardware from damage and reducing the threat of leaks.

Aviation specifications

Corrosion inhibitors are commonly specified in aviation fuels – often referred to as Corrosion Inhibitor/Lubricity Improvers (CL/LI) – as a solution to help in the reduction of engine wear. Innospec’s approved aviation fuel corrosion inhibitors serve a dual function – they improve the fuel’s lubricity as well as protecting the fuel system against corrosion.

Solutions for every requirement

Innospec’s corrosion inhibitors are designed to meet the wide range of approvals commonly required for corrosion inhibitors in both ground and aviation applications. Two products in the range are approved for use in jet fuels.

Our range includes:


DCI-4A, part of Innospec’s range of corrosion inhibitors, has extensive aviation and ground fuel approval.

The preferred inhibitor for aviation fuels, DCI-4A’s approvals include:

Jet fuel lubricity additive
MIL-PRF-25017*                      DEF STAN 68-251
Civil aviation turbine fuel
AFQRJOS / JSCL                      ASTM D1655
Military aviation turbine fuel
MIL-DTL-5624                      DEF STAN 91-87
MIL-DTL-83133                      DEF STAN 91-91
DEF AUST 5208                      DEF AUST 5240
NATO (including NATO Pipeline System)
STANAG 3390                     STANAG 7036 (NPS)

DCI-4A has a low effect on MSEP and other water interactions, when compared to competitive corrosion inhibitors.

The treat rate range for DCI-4A in ground fuels is typically 6-12mg/l.

*DCI-4A has the following class-leading concentration approvals for Category 1 additives in MIL-PRF-25017:

  • REC = 6mg/l
  • MEC = 9mg/l
  • MAC = 24mg/l

A ‘stronger’ corrosion inhibitor than DCI-4A, DCI-6A has an extensive heritage and remains the preferred choice for use in today’s finished fuel pipelines.

The inhibitor is preferred for all ground fuels and for pipeline corrosion protection, due to its low treat rate.

DCI-6A is also extensively approved for aviation fuel use.

The approvals for DCI-6A include:

Jet fuel lubricity additive
 MIL-PRF-25017* DEF STAN 68-251
Aviation turbine fuel
MIL-DTL-5624 DEF STAN 91-87
MIL-DTL-83133 DEF STAN 91-91
Ground fuels
MIL-PRF-25017 (Cat.1) VV-F-800D (Diesel)

*DCI-6A is approved under Category 1 additives in MIL-PRF-25017 at the following concentrations:

  • REC = 6mg/l
  • MEC = 9mg/l
  • MAC = 15mg/l

The treat rate range for DCI-6A in ground fuels is typically 3-9mg/l.


As part of our corrosion inhibitor range, we offer DCI-11, a formulation developed specifically for use in fuel-grade ethanol.

This product was developed to solve unique corrosion problems that emerged after the launch of Gasohol. DCI-11 does not just act as a corrosion inhibitor; it also serves an ethanol stabilizer providing a pHebuffering effect.

DCI-11 is designed to treat ethanol, rather than the fuel. When additizing ethanol, elevated dosages of DCI-11 are required to provide a treat rate equivalent of 6-12mg/l in finished fuel.

DCI-11 Plus

DCI-11 Plus is a multipurpose additive for use in gasoline, fuel ethanol and fuel oxygenate blends. It is a specially formulated corrosion inhibitor for improved pHe control and excellent low temperature handling.

DCI-11 Plus contains a concentrated corrosion inhibitor and enhanced amine buffer to neutralize pHe.

At the recommended treat rate, DCI-11 Plus offers:

  • Excellent cost effective corrosion protection
  • Reduction of fuel pump wear
  • Protection of critical steel, terneplate and modern alloys in fuel injection systems
  • Corrosion protection for the entire life of the fuel
  • Long term protection for storage tanks and fuel handling assets
  • Effective neutralization of pHe to meet fuel ethanol specification standards

The treat rate range for DCI-11 Plus is typically 30-86mg/l.


DCI-30 is a synthetic, caustic resistant, sulfur compliant corrosion inhibitor which provides excellent protection in gasoline and distillate fuels during pipeline transfers and storage.

The treat rate range for DCI-30 is typically 3-9mg/l.


DCI-35 is an ashless sulfur corrosion inhibitor, designed to prevent the corrosion of non-ferrous metals.

It is particularly useful in protecting copper and copper alloys against attack by active sulfur and sulfur compounds in the fuel.

The typical treat rate for DCI-35 is from 100mg/l.