VALVES & FITTINGS
“Perhaps one of the most well
recognised benefi ts of plastic push-fi t
fi ttings is the fact that no additional tools
are required to complete installation”
Making the most of
push and press fi t
Installers are always looking for plumbing and heating products
that offer time and cost savings, without compromising on system
performance. Steve Harris, technical service engineer at Wavin
Hep2O, explores the differences between press and push fi t
fi ttings, detailing the benefi ts of each, as well as explaining where
one may be better suited over the other for specifi c installations.
Push-fi t fi ttings have been key in
helping installers save time on
site since they were fi rst created
in the 1970s. Now, these fi ttings
are an essential piece of equipment for
commercial and domestic hot and cold
Perhaps one of the most well recognised
benefi ts of plastic push-fi t fi ttings is the
fact that no additional tools are required
to complete installation. Once the pipe
has been measured and cut to length,
installers simply connect it to the fi tting –
making the installation quick and easy.
Plastic plumbing pipe is usually made
from one of two materials, polybutylene or
cross-linked polyethylene (PEX-c).
Polybutylene is the most popular
material used in both RMI and new
build applications, thanks in part to its
unrivalled fl exibility.
TIME SAVED ON PROJECTS
Despite being wound on large drums when
in storage, polybutylene retains its integrity
when uncoiled. This means the pipe is able
to remain straight and can be put to use
soon after it is removed from the drum,
ensuring no time is wasted on project
By contrast, PEX-c pipe is relatively stiff
and when taken from the coil retains a
‘spring’ like quality.
Although PEX-c pipe is still used by
some installers in the UK, many are now
opting to use to polybutylene as it is easier
to work with in situations such as cabling
through joists and between walls, where
fl exibility is essential in saving time.
The enhanced fl exibility of push-fi t
systems also means they are ideal for use in
underfl oor installations. Whether using a
plate system or staple system, the pipe can
be laid in any shape necessary.
Press-fi t fi ttings have also become
It is for this reason that press-fi t systems
are a popular choice for recirculating
systems, which are most commonly used
in hospitals and hotels where there is a
continuous need for a hot water supply.
MAKING THE MOST OF PUSH AND
While the specifi c benefi ts of each system
may be well known in the industry, what
is perhaps less well recognised is that by
integrating both push and press fi t fi ttings
into projects, installers can create systems
with more effi ciency than ever before.
For example, in projects involving highrise
apartments buildings push
and press-fi t fi ttings can be
used in conjunction.
Installers can utilise push-fi t
fi ttings for the self-contained,
individual apartments within
the building, while opting for
use press-fi t fi ttings to provide
the plumbing and heating for
the plumbing infrastructure.
Where there is a transition
from one system to another
Hep2O has an adaptor fi tting
that makes the process simple
While effi ciency in installation
may be one of the biggest factors to
consider when selecting a plumbing and
heating system, it’s also important to
think about the longer-term effects of
product selection, and ongoing system
Hep2O’s push-fi t system carries a
number of British Standards including
BS 7291 – thermoplastics pipe and fi tting
systems, BS EN ISO 15876 – plastics
piping systems for hot and cold water
installations, and BS EN ISO 21003 –
multilayer piping systems. Hep2O fi ttings
are also guaranteed against defects in
materials and manufacturing for 50 years.
K1 press-fi t offers a number of
additional guarantees too, including
DVGW and KIWA European approvals
and certifi cation to EN-ISO 21003.
For end users, product guarantees such
as these give added reassurance that their
plumbing and heating system will function
effectively, and effi ciently, for years to
ENQUIRY NUMBER 133
offering similar benefi ts
and enhanced safety
installers working on
large scale projects.
Like push fi t fi ttings,
press-fi t systems offer
over more traditional
options such as
copper. There are
a number of safety
precautions to take
and hot works are
required to make a secure
In such instances,
both push and press-fi t
fi ttings offer installers
an alternative solution as welding is not
required. This is particularly benefi cial in
installations where space is limited.
Some press fi t systems, such as K1
from the manufacturer of Hep2O,
feature multilayer composite pipe.
This is comprised of an inner plastic
layer made of cross-linked polyethylene
(PEX-c), an outer plastic layer of high
density polyethylene, and a butt-welded
aluminium layer in between.
The aluminium layer in the pipe
reduces thermal expansion (with a
performance comparable to copper)
and acts as an oxygen diffusion barrier,
preventing corrosion and any biofi lm
There are some applications where
it is more benefi cial to use one type of
fi tting and system over the other, and
the fact that press-fi t systems are multilayered
Press fi t systems,
such as K1 in-situ,
means they can withstand higher
temperatures than other systems.
70 Heating & Plumbing Monthly | OCTOBER 2018 | www.hpmmag.com