CPVC Compatibility Letter

Hilti North America
USA: 1-800-879-8000; www.hilti.com
Canada: 1-800-363-4458; www.hilti.ca
August 27
th
, 2020
Re: CPVC Compatibility with Hilti Sealants and Chemical Products
Pipe made of Chlorinated Polyvinyl Chloride (CPVC), has been used in general
plumbing for over 50 years and extensively in fire sprinkler systems for over 35
years.
1
CPVC has many benefits and advantages, however chemical resistance
issues can appear when the CPVC is exposed to, or comes in contact with, materials
the CPVC is not compatible with. This contact combined with numerous other
factors such as, temperature, environment, etc, can cause issues in the CPVC. These
issues may show up in the pipe years after installation, as softening, degradation, or
environmental stress cracking (ESC).
2
For these reasons it is important for those
working on or around CPVC to verify it is compatible with the products that may
come into contact with CPVC – even if inadvertent.
3
Since the compatibility issue is unique, and specifically related, to the CPVC, CPVC
pipe manufacturers have undertaken the responsibility to develop programs to
determine compatibility with ancillary products expected to contact their pipe –
glues, primers, firestop, sealants... – and publish a list of compatible products. Due
to variations in CPVC formulation and testing procedures, these compatibility lists
may differ between CPVC manufacturers. Therefore: only apply ancillary
products which are specifically approved for use on the brand of CPVC being
used. If an ancillary product is not on the compatibility list, contact the CPVC
manufacturer before use. Never assume the absence of a prohibition indicates
suitability, because many ancillary products have a variety of applications and their
manufacturers typically do not address incompatibility.
4
If there is not an affirmative
statement of compatibility by the CPVC manufacturer for an ancillary product, do
not use it on CPVC!
1
https://plasticpipe.org/building-construction/bcd-cpvc.html
2
https://www.corzan.com/en-us/chemical-resistance-and-chemical-applications
3
E.g., cabling draped across the CPVC pipe, or overspray from other activities.
4
I.e., manufacturers identify their products’ intended applications. It is generally not
feasible to attempt to identify and list every unintended use that may be problematic.