White Paper 1
When put to
the test a
sound
argument
delivers cast
iron evidence
Mike Rawlings of Saint-Gobain
PAM UK describes how testing to
the new European standard has
brought closure to the debate on
which is the optimum material for
above ground drainage systems
Introduction
requirement for above ground drainage
Structure-borne and airborne sound
applications across a broad spectrum of
between rooms generated by the
commercial and public building
evacuation of waste water has grown into
applications. Typically, these would
a key issue in above ground sanitary
include quality flats and apartments,
applications and has resulted in varied and
hotels, schools, hospitals, libraries,
potentially misleading communications
universities and prisons.
about the comparative sound-absorbing
qualities of a cross-section of materials
Acoustic performance
used for these systems. Noise usually
Over time, the acoustic debate has
occurs as a result of a mixed flow when
reached a level where it has become
the pipe is filled with water and air, when it
probably second in importance only to fire
will radiate noise outwards and transfer it
safety. Judging the acoustic performance
to any lightweight ceilings, cupboards and
of different materials is difficult enough for
similar areas wherever it makes contact.
any acoustic engineer, let alone an
architect, specifier or installer and this has
allowed many materials to promote
themselves as the best acoustic option,
even with little or no comparable data for
anyone to make an informed choice. What
was needed was a method for accurate,
comparative laboratory testing covering
different materials to provide
manufacturers of all drainage materials
with simple testing criteria and limits for
different situations.
Relevant regulations
UK Building Regulations Document E
1
Resistance to the Passage of Sound
provides some guidelines on acoustic
levels in residential dwelling houses and
flats for separating walls and stairs with
separating functions, and general
pipework next to habitable rooms,
Meanwhile, BS 8233:1999, a code of
Alongside fire resistance, strength, low
practice for governing acoustics within
maintenance, ease and speed of
buildings, suggests acoustic levels by
installation and longevity, silence in
building type, such as office, library or
operation can be a particularly important
bedroom, and provides details of acoustic
insulation and the estimated insulation
specifiers to choose the most appropriate
value of each.
drainage system for the building type
based on the level of acoustic
A new European Standard
performance required.
Accepting the need within the above
ground drainage sector for a universal
Putting drainage materials to the test
acoustic testing method that covered a
As a global leader in iron technology,
cross-section of the primary materials
Saint-Gobain PAM had long held the belief
used for waste water systems, the
that cast iron outperformed rival materials
CEN/TC 126/ WG1 working party was
in above ground drainage systems and,
established by the CEN (European
alongside similar convictions held by
Committee for Standardization) to develop
proponents of plastic and steel systems,
simplistic testing criteria to enable all
voiced its claims accordingly.
materials and systems to be tested in the
same fashion and to the same standard
Cast iron had already established its
(see diagram of criteria below).
credentials as offering high levels of
performance in terms of proven longevity,
strength, and sustainability, being made
from 97% recycled materials. Additionally,
tests carried out in 2004 in Germany at the
North Rhine West Phalia Laboratory in
Germany, commissioned by IZEG
By allowing accurate comparisons, the
(German association of Cast iron
tests would provide specifiers with the
manufacturers), proved it to be the one of
relevant information required to help them
safest drainage materials to specify with
make a more informed choice. As a
regard to fire resistance. The introduction
result, the new European standard, BS EN
of BS EN 14366:2004 provided the perfect
14366:2004, was introduced to specify a
platform to enable comparative noise
method for accurate and comparative
transmission tests measuring the five
laboratory testing.
competing materials and perhaps place
the final piece in the cast iron jigsaw.
The standard requires the measurement of
In an effort to use the benchmark of BS
airborne noise (pipework in the same
EN 14366:2004 as a means to bring the
room), and structure-borne noise
‘materials’ debate to closure, Saint-Gobain
(measurement taken in the adjacent
PAM initiated acoustic tests on its leading
room), at an accredited testing laboratory,
products, Ensign and Ensign EEZI-FIT,
at specific flow rate levels depending on
and a number of competing materials by
diameter. In addition, it calls for testing to
submitting them to the IBP Fraunhofer
be carried out on all bracketry to provide
Institute Laboratory in Stuttgart, Germany
independently assessed results to enable
in 2009.
joints. For this test, the Ensign EEZI-FIT
system was also fitted with two EF048AD
acoustic brackets.
Quietest drainage system
The noise level recorded for the
mechanically jointed Ensign system was
exceptionally low, recorded at 11dB(A) at
4 litres/second for structure-borne
measurement and 47dB(A) for airborne
measurement when installed using the
ductile iron bracket fitted with the acoustic
dampener. This test verified cast iron, as a
material, to be quieter than the plastic
system tested by up to 6-9dB(A) and up to
20dB(A) quieter than standard HDPE for
structure-borne noise.
To cater for the distinct Ensign system
options, two tests were carried out,
comparing each system option separately
with the rival drainage materials.
Option 1 encompassed Ensign pipework
When testing the Ensign EEZI-FIT push-fit
fitted with two EF048AD acoustic brackets
system, the noise levels were reduced by
in 100mm diameter. The second option,
a further 2dB. Ensign EEZI-FIT recorded a
100mm Ensign EEZI-FIT, added a new
sound level of 9dB(A) at 4 litres per
push-fit jointing system to the mix. The
second and 4dB(A) at 2 litres per second,
Ensign EEZI-FIT product was designed to
which is significantly quieter than a
bring faster installation through push-fit
recently introduced plastic system
assembly. This was highlighted in a study
boasting 12dB performance which under
carried out in 2009 at the Building
closer scrutiny is at 2 litres per second.
Research Establishment (BRE) where,
under strictly monitored conditions, Ensign
Further testing on the Ensign system at 8
EEZI-FIT was shown to be substantially
litres per second, double the flow required
faster to install over a 9m high vertical soil
by the standard, showed it performed to
riser than HDPE using fusion welded
the same level as acoustic plastic systems
at 4 litres per second. Also, 150mm
diameter Ensign was tested at 8 litres per
second equalling the performance of the
best of the rest using 100mm pipework.
At a flow rate of 4 litres per second, the
Ensign EEZI-FIT system recorded a sound
level 15-17dB(A) lower than stainless
steel, 20dB(A) lower than HDPE, 910dB(A) lower than acoustic plastic and
costs rather than initial purchase cost. If
10-12dB(A) lower than acoustic HDPE.
acoustic performance is high on the
specification, other materials need
expensive insulation to match the
performance of Ensign cast iron. Other
materials may also need more bracketry
according to the BS EN 12056:2000
guidelines, which means more fixing time.
The low level of acoustic noise generated
by Ensign and Ensign EEZI-FIT cast iron
systems, installed using the acoustic
bracket, shows there should be no
Part E of the Building Regulations advises
requirement for insulation wrapping when
that all pipes should be lagged when pipes
passing through habitable rooms.
and ducts are penetrating floors
separating habitable rooms. However, for
In time, the evidence demonstrated by
airborne noise, the level achieved by both
these test results should not only bring
the Ensign and EEZI-FIT systems, implies
closure to the long-running acoustic
that when covered by standard plaster
debate, but should also enable all parties
board, both would achieve the general
involved within the above ground drainage
acoustic requirement of 30-35dB(A)
industry to be in accord when it comes to
without the need for lagging.
selecting the most effective and efficient
The test also established that twin-wall
material and system for the evacuation of
PVC, HDPE and stainless steel materials
waste water from sanitary installations
when fitted with their acoustic rubber lined
within buildings.
brackets would require substantial
insulation to match the performance of
For further information visit www.eezi-
cast iron.
compare.com
When comparing the costs of drainage
materials, architects, specifiers and
installers need to focus on total installed
Appendix 1
Full results of testing at the IBP Fraunhofer Institute Laboratory, Stuttgart, Germany