Select the Material and Chemical to be used and then click Submit.
Over the years, we have constantly sought to provide new and better products
as they become available and are consistent with our goal of selling the best
at the most economical cost.
Engineers must carefully select materials for vessels, piping, pumps and gaskets
when designing systems for handling corrosive chemicals. With a relatively
recent awareness of environmental issues, engineers’ jobs take on a new
Designing a system for a specific application usually involves referring to
several sources on piping, tanks, pumps and elastomer seals. Until the advent
of synthetics, such as plastics, choices were limited to various grades of
metal and alloys. Now the field is greatly expanded. In this Chemical Resistance
guide, Harrington has provided a single resource of non-metallic and high-purity
steel products based on manufacturers' recommendations and our own extensive
experience. It is important to note that these tables should be used only as
a guide. In all cases, a physical test of the material under actual operating
conditions is the only way to ensure the success of a particular material for
Engineers must take into account changes in internal and external temperatures
and pressures, the affects of UV and mechanical stresses.
Corrosion is defined as a gradual wearing away. This is an accurate definition
when dealing with metals. With non-metallic materials, such as plastics, there
is no rate of corrosion; they are either resistant or they deteriorate completely
from a chemical compatibility stand point. However, it must be remembered that
mechanical stresses will limit the useful life of a piping system. In the case
of poor chemical resistance, the failure of the piping system is hastened by
Metals tend to form a passive film on the surface to resist corrosion. Rust
is a chemical reaction that forms iron oxide on iron and steel. Stainless steel
is frequently treated with dilute nitric acid to produce an oxide layer on
the surface which makes the material more resistant to chemical attack. While
this surface layer slows the corrosive degradation, metals still exhibit a
penetration rate of the aggressive chemical. An A-rating for metals means that
the rate of penetration is <2
mils per year. A B-rating means that the rate is <20 mils per year and with
a C-rating, the rate can be estimated at <50 mils per year.
Metals are listed as:
A = Excellent
B = Good, minor effect
C = Fair, needs further test
X = Unsuitable
Higher temperatures generally hasten the corrosion reaction that results
in material failure. In the tables provided here, temperatures shown are
the maximum that can be used for the specified plastic in the particular
chemical application. Plastics also have low temperature limitations at
which they may be used successfully. These tables do not address this issue.
Harrington welcomes your specific inquiries.
There are many variables that contribute to the successful use of a particular
material, whether it is metal or plastic. There are many different plastic
compounds and formulations. A material determined suitable for a specific chemical
application does not mean that the compounds of that plastic from all manufacturers
can be considered suitable. A dash means we lack sufficient data.
Polyethylene tanks that are manufactured with HDLPE (high density linear polyethylene)
can handle applications to 130°F. Polyethylene tanks manufactured with
XLPE (cross-linked polyethylene) can handle applications to 140°F. It is
important to note that tanks designed according to ASTM D 1998 are designed
based upon 73.4°F. Snyder Industries exceeds ASTM D 1998 by designing its
tanks based upon 100°F (ambient conditions).
As per ASTM D 1998, applications that will exceed 73.4°F, (100°F for
Snyder tanks), need to be designed based upon the specific chemical application.
When designing tanks for applications above 100°F, the manufacturer needs
to take into consideration the chemical, its concentration, and temperature.
(per ASTM D 1998-97 section 6.1.2 - All tank hoop stress shall be derated for
service above 23 degrees C/73.4°F).
To the best of our knowledge, the information contained in this publication
is accurate. However, we do not assume any liability whatsoever for the accuracy
or completeness of such information. Moreover, there is a need to reduce human
exposure to many materials to the lowest physical limits in view of possible
long-term adverse effects.
To the extent that any hazards have been mentioned in this publication, we
neither suggest nor guarantee that such hazards are the only ones that exist.
Final determination of suitability of any information or product for the use
contemplated by any user, the manner of that use, and whether there is any
infringement of patents, is the sole responsibility of the user. We recommend
that anyone intending to rely on any recommendation, or use of any equipment,
processing technique, or material mentioned in this publication verify that all applicable safety and health
standards are met. We strongly recommend the users seek and adhere to manufacturers’ or
suppliers’ current instructions for handling each material they use.
COMPRESSED AIR AND GAS
Plastic Piping Systems designed for corrosive and/or high purity liquid service
are not recommended for Compressed Air or Gas applications.
There are a few specially designed thermoplastics piping systems that are
suitable for selected Compress Air or Gas applications. Consult your local
Harrington Office for recommendations.
USE OF THE CHEMICAL REFERENCE TABLE
The aggressive agents are classified alphabetically according to their most
common designation. Further descriptions include trivial and common names as
If several concentrations are given for a particular material, the physical
data, in general, relates to the pure product that is 100% concentration.
In listing the maximum use temperature for each plastic type in a given chemical,
it can, in general, be assumed that the resistance will be no worse at lower
HOW TO SELECT THE CORRECT MATERIAL:
1. Locate the specific chemical in the guide.
2. Select the material with a maximum use temperature that matches or exceeds
the need. The Harrington philosophy has always been to suggest the least costly
material that will do the job.
3. Where a material or elastomer appears to be marginal compared to the requirements,
place a call to our technical staff for additional recommendations.
1. Methylene chloride: in the table PVDF, Halar, or PTFE are the only materials
suitable. Carbon steel works well for chlorinated hydrocarbons of this sort,
and that would be our choice unless there was another reason to justify the
higher cost of PVDF, PTFE, or Halar.
2. Sodium hypochlorite, 15% at 100°F: PVC is good to 100°F and is
the least expensive of the materials available, however, you must use 724 CPVC
cement for this and caustic applications.
3. For nitric acid, 40% at ambient temperature: the tables recommend either
CPVC or polypropylene at 73°F. In most cases, CPVC will be the economical
choice. Note that PVDF is rated for higher temperature use.
Note: The ratings shown for carbon and ceramic pump seals are approximate.
Please contact your local Harrington service center for a recommendation on
your specific application.