ARMACELL INSULATION PROTECTS WWT PLANT FROM WEATHER EXTREMES
The Scottish Highlands are no stranger to cold weather but
the winters of 2010 and 2011 were severe even for this part
of the world, with temperatures regularly reaching –15 ºC.
The town of Fortrose located on the Moray Firth, about 10 km
north east of Inverness, was certainly no exception as the
small coastal burgh is exposed to all the elements the cold
North Sea has to throw at it.
So when Inverness based mechanical and electrical engineers
Commissioning Solutions Scotland were appointed to replace
failed process pumps for the local waste water treatment
facility, careful consideration had to be given to the
insulation material used to protect the equipment and
process flows from freezing.
For this challenging and exposed environment David Hawthorn
of Commissioning Solutions Scotland, working in conjunction
with thermal insulation contractors McDonald & Co, specified
Armacell’s Class O Armaflex nitrile rubber insulation
material.
Armaflex offered a number of benefits for this application
over the conventional glass fibre insulation material which
had previously been used and failed on site. Glass fibre or
mineral wool insulation is reliant on an easily punctured
external foil vapour barrier to prevent moisture ingress. If
this barrier is compromised, the result is wet insulation
that causes Corrosion Under Insulation (CUI) and loss of
thermal performance, especially in tough conditions such as
those encountered at the Fortrose waste water treatment
works.
As a closed cell foam material, Armaflex provides an
integral vapour barrier against water ingress and
condensation, with no additional water vapour barrier
required. The material has a moisture resistance factor of
>7,000 µ so even if the material becomes damaged in some
places, it will still provide protection against
condensation and water ingress as the closed cell structure
is built-up throughout the material’s thickness.
The thermal conductivity of Armaflex is 0.034 W/(m • K) at 0
ºC meaning, at outdoor temperatures of –15 ºC and initial
line temperatures of 7 ºC, a 25mm layer of Armaflex will
provide over 40 hours of frost protection on an 89 mm
diameter steel pipe or 52 hours on a 114 mm diameter pipe
when containing static fluids. Local water supply
regulations specify 12 hours protection at ambient
temperatures of –6ºC so the 25mm Armaflex well exceeds these
minimum requirements.
Due to its flexible foam structure Armaflex sheet can be
easily cut and fabricated to cover fittings, pumps and
valves. For outdoor use Armafinish 99 paint is required to
provide protection against UV degradation. Alternatively
HT/Armaflex UV resistant EPDM rubber material can be used
without the need for additional painting.
For additional protection against mechanical impact (or even
seagulls and rodents using the material for nesting)
Armacell’s flexible Arma-Chek R covering or as was the case
at Fortrose, metallic cladding can be used.
Owner of McDonald & Co thermal insulation contractors, Frank
Cameron, has been an advocate of Armaflex insulation for
many years and even during the exceptionally cold winters
has never had any failures of equipment with the nitrile
rubber material. Frank explained “on the large number of
water facilities projects I have worked on over the years,
Armaflex has offered the most reliable performance in cold
weather. Add to this the ease of installation and
affordability of the material, it is the best choice for
providing frost protection in extreme weather conditions.”
For colder processes such as cryogenic applications, Armacell has recently
developed Armaflex LTD utilising a diene terpolymer with a
much lower glass transition point. This is the point
(-50°C), where the mechanical behaviour of conventional
nitrile rubber materials change, with the rubber
increasingly losing flexibility through hardening. However,
the Armaflex LTD products maintain full strength and
flexibility over the temperature range of -200°C to +125°C.
This ensures that vibration and impacts can be absorbed,
with the risk of cracking from extreme temperature cycling
or mechanical strain considerably reduced. The closed cell
material has a very low thermal conductivity and also a high
resistance to water vapour transmission providing a
‘built-in’ vapour barrier. These characteristics reduce the
risk of CUI, providing significant savings on installation,
while the cryogenic foams, unlike rigid foams, also
eliminate the need for expansion joints or additional vapour
barriers to achieve even further installation savings.
Further information is available on request:
Armacell UK Ltd
Mars Street
Oldham
Lancashire
OL9 6LY
Tel: 0161 287 7040
Fax: 0161 633 2685
info.uk@armacell.com
www.armacell.com/uk
Further Information
Armacell is a manufacturer of engineered foams and the world leader in the market for flexible technical insulation materials. In the financial year 2010, the company had a gross annual turnover of around 427 million Euros. The group of companies has approximately 2,500 employees and 18 factories in 12 countries. It is headquartered in Münster, Germany. Apart from ARMAFLEX the leading brand in the field of flexible technical insulation, the company also produces thermoplastic insulation materials, covering systems, fire protection and noise control products, special foams for a multitude of industrial applications and foam cores which are used as composite materials.
