Aeroflex EPDM Insulation

Aeroflex EPDM Insulation

AEROFLEX Closed Cell Tube and Sheet Insulations are expanded, closed-cell, sulfur-cured rubber type compounds. They contain synthetic polymer, fillers, plasticizers and rubber chemicals.

The main ingredients are:

·        Synthetic rubber (EPDM: Ethylene-Propylene-Terpolymer Rubber) CAS No.25038-36-2

·        Aluminum Trihydrate CAS No.21645-51-2

·        Carbon Black CAS No.1333-86-4.

AEROFLEX is an ideal insulation for hot and chilled water pipelines. It prevents heat gain and condensation problems on chilled water/refrigerant pipelines, and prevents heat loss from hot water plumbing, liquid and dual temperature pipelines.




Aeroflex Tube Insulation

AEROFLEX is easily installed to tubing. The factory applied coating of talcum powder on the thick and smooth inner skin helps facilitate and speed up preassembly lines. When applied to existing lines, tubing should be slit length-wise and snapped into place. Slitting can be done on the job easily with razors, blades, knives or shears. Cut edges and joints can be sealed with Aeroseal Adhesive (neoprene base contact cement).

Aeroflex Continuous Sheet Roll (SR-series)

AEROFLEX sheet insulations are available in continuous roll form. The continuous sheet rolls are available from 1/8” (3mm) to 2” (50mm) in thickness, 4 feet in width and 8 feet to 150 feet in length.


Aeroflex-SSH is a new, flexible high-temperature insulation material which is applicable in the fields of sanitation, solar setups and heating. It is CFC and PVC free and has excellent UV and weather resistant properties. For more information, check out Aeroflex-SSH.pdf


Grade Specification





Cell Structure

Closed Cell


Density Ibs/ft3(kg/m3)

3-6 (48-96)

ASTM D 1667

Thermal Conductivity



32 oF




ASTM C 518, C 177 o hr. oF (W/mk)


(-20 oC)

(0 oC)

(24 oC)

(32  oC)

(40 oC)

JIS A 1412








DIN 52613
















Service temperature

-70oF to 257oF

AEROFLEX becomes

-57 oC - + 125 oC

Hard at -57oC, but


Can be used even at -200oC



Water Vapor permeability (g/Pa.s.m)



0.10 perm-in (1.44x10-10)




Moisture Resistance


DIN 52615

(µ value)

µ 7000

Water Absorption (% by weight)


ASTM D 1056

Ozone Resistance

No crack

ASTM D 1171, D 1149

Heat Stability (% shrinkage)


ASTM C 534

200 oF (93 oC) 7 days

Flammability & smoke, Density

Class  V O

UL – 94



Self – extinguishing

ASTM E 635



Class 5.3

EMPA  (Switzerland)


JIS K 6911



U.V. Weather Resistance



Corrosion of copper, stainless

Non corrosive

DIN 1988

Nitrosamine Contents

Not Detected


Sound reduction (LAF)

27  dB (20 mm)

DIN 52218





Specifications Company ASTM C534

 Figures show the average values obtained by the world renowned testing institutes

Tested according to DIN, JISASTM and others

Average density of insulation thickness 20 mm is 2.5 – 5 lbs/ft3 (40 – 80 kg/m3)

At temp. under -57°C, AEROFLEX becomes hard, but it doesn’t affect the thermal conductivity or water vapor permeability.

            In the heating applications, AEROFLEX can stand +125°C continuously, and the adhesive up to +100°C

IMO : International Maritime Organization fire test procedures code part 5 and part 2 [IMO res.A.653[16]]

            -Lloyd’s type approval certificate

            - DNY’s type approval certificate

It is reported that Nitrosamine is harmful to human health even during storage. No Nitrosamine compound was detected in AEROFLEX.




Chilled water piping


Hot water piping


Refrigerant piping


Duct insulation


Roof, raised floor and under slab insulation


AC unit insulation (internal insulation of units, evaporators, etc.)


Clean room, cold storage and solar plumbing applications


Transport segment AC units


General thermal insulation (large diameter pipes, tanks, vessels etc.)

 Characteristics and Main Advantages: 


Thermal Efficiency & Temperature Range





AEROFLEX has a stable low K factor of 0.25-0.27 (at 50F-90F mean temperature) which can save energy consumption on any heating/cooling lines. Also, it can be used in operating temperatures between -57 C (70F) and +125C (257F), without affecting the thermal efficiency or water vapor permeability.


Moisture & Weather Resistance

AEROFLEX is made from selected high molecular weight synthetic elastomers to obtain outstanding weather resistance. Also, its closed cell structure acts as multiple layers of vapor barriers to maintain stable K value over long service life, thus eliminating the need of vapor barriers in most applications.


Flame & Smoke Proof

AEROFLEX Tube and sheet Insulations have been specially compounded to meet the ASTM Standard No. D 635, UL-94 V, JIS No. K 6911 and other standards.
The products have low smoke density while burning, and unlike other thermoplastic materials, AEROFLEX will neither melt nor drip flaming balls, and will therefore prevent flame transfer.


Easy Installation & Anti-vibration

The flexibility and smooth surface of Aeroflex enables quick, easy installation and neat-finished appearance. Moreover, its high elasticity minimizes the vibrations and resonance of pipelines during operation.


Other Advantages

AEROFLEX can be safely handled without causing skin irritations and health hazard. It has superior resistance to fungus growth, vermin/rodent attack and other chemicals such as acids and alkalis. These properties make AEROFLEX ideal for protecting piping from corrosion caused by atmospheric agents and industrial ambience.

Aeroflex is widely used in indoor and outdoor heating and cooling systems to replace fiberglass and calcium silicate. For flexibility and outstanding durability, it is the most suitable insulation for split type air conditioners.





NBR Products


Raw Material

EPDM – Few double bonded molecular structures in a strand





NBR + PVC - More double bonds in a strand

Because of more double bonds in NBR/PVC, not all bonds are linked when cross-linking occurs, thus leading to high probability of surface and mass deterioration in a short time.

EPDM has fewer double bonds and most of the double bonds are linked, so there is a very low chance of surface and mass deterioration.

Chemical Name of Raw Material

Ethylene Propylene Diene Monomer (generally known as Ethylene Propylene Terpolymer)

Acrylonitrile (Vinyl Cyanide) + Poly Vinyl Chloride

Acrylonitrile, the main constituent of NBR, is a toxic chemical and is listed in the U.S Fire Administration as Hazardous Material.


3 – 6 lbs/ ft3

(48 – 96 kg/ m3)

Each brand has different density but most range from 2.5 – 8 lbs/ ft3

(40-128 kg/ m3)

According to theory of Thermal Insulation, generally, a density of 3 – 6 lbs/ ft3 (48 – 96 kg/ m3) is considered as the ideal density for low thermal conductivity. Aeroflex uses this theory and applies it to production process while considering the water vapor absorption and permeability properties.

If density is lower than 3 lbs/ ft3 (48 kg/ m3), the cell wall will be thin and will break due to vapor pressure in the atmosphere causing the insulation to absorb water vapor/ moisture resulting in higher thermal conductivity and rise in energy bills.

If the density is higher than 6 lbs/ ft3 (96 kg/ m3), the cell wall will be thicker, hence promoting higher conduction, convection rate and bigger cells, which will increase the thermal conductivity.



Cell Structure

Small cell structure

(closed cell structure)

Bigger and rough cell structure

(closed cell structure)

AEROFLEX is made with fine cell structure which promotes slow conduction period & high resistance to flow of heat transferred by convection from one side of the cell to the other, resulting in low and stable thermal conductivity throughout.

On the other hand when the cell structures are big, there are fewer of them in the insulation, causing heat transfer from one cell to other, and heat flow from one side of the cell to the other, both at a faster rate, resulting in higher thermal conductivity. 

Outside and inside surface of insulation tube

Dense skin inside as well as outside

Dense skin outside but no or very sparse (thin) skin inside

AEROFLEX has a very dense skin on the outer as well as inner surface of the tube, thus creating a perfect vapor and moisture barrier on cooling lines.

 While NBR/PVC has dense skin on the outside, most producers compromise on the inner skin. Thin inside skin has the vulnerability of absorbing moisture and vapor from the inside, if there is residue of moisture present between the insulation and piping during installation. Furthermore, the polarity of the material itself attracts water.

Polarity to Water



NBR/PVC products have the same polarity as water; hence they absorb water, lose insulation property and increase the thermal conductivity.

EPDM, being non-polar doesn’t attract water molecules and hence, retards water vapor and moisture.

Weather and UV Resistance



Aeroflex is made of EPDM which itself has very good UV and weather resisting properties. EPDM is used in making various automotive parts including window strips where UV & Weather resistance is required. Aeroflex has been installed in some severe regions where the weather patterns are extreme (-15°C in winter & +45°C in summer).

As NBR is a polar material, the insulation deteriorates and cracks when exposed to weather or ozone. It is recommended to paint the insulation or install a barrier against weather and ozone.

Thermal Conductivity

0.037 W/mK at 24°C (0.25 BTU. in/ft2. hr. °F at 75°F) in accordance with ASTM C177 & DIN 52613

Each brand of NBR/PVC based insulation has different thermal conductivity ranging from 0.037 ~ 0.045 W/mK at 24°C (0.25 ~ 0.30 BTU. in/ft2. hr. °F at 75°F) in accordance with ASTM C177 & DIN 52613





Aeroflex uses EPDM as its main raw material with a blending technology, cross-linking the cell structure to produce closed cells with a dense surface skin on outer as well as inner surface.


NBR/PVC is also vulcanized to create a cross-linking structure but due to too many double bonds in the raw materials, not all are bonded and cross-linked, producing a sparse skin outside as well as inside with a bigger cell structure resulting in a higher thermal conductivity.










-57°C ~ 125°C (-70°F ~ 257°F)

-40°C ~ 105°C (-40°F ~ 221°F)

Glass transition of NBR/PVC is approx. -20°C (–4°F) i.e. at this temperature the insulation becomes hard & brittle and is difficult to install.

Glass transition of EPDM is approx. -50 °C to -60°C (-58°F to -76°F).

Most of the rubber insulations are cross-linked polymers (thermosetting), and won’t melt at high temperatures. Service temp. for NBR is 105o C while for EPDM it is 125o C

Physical Strength



NBR/PVC based insulation has better tensile strength and better reformation.

Aeroflex is weaker physically but is easy to cut for neat and tidy jobs

Corrosion of Copper/Steel

Very good resistance to corrosion

Fair resistance to corrosion

Aeroflex uses a small amount of Chlorine and Bromine in the production process. It can even be used on stainless steel pipes without any concern about corrosion.

NBR/PVC blended products have a high amount of Chlorine (PVC itself has a chloride in it) and Bromine as fire retardants, resulting in corrosion of copper and stainless steel pipes. The manufacturers of NBR/PVC products recommend not using their products for stainless steel piping or ducting

Water Absorption

Less than 5% by weight

Each brand has its own absorption rate but most lie between 5 – 20% by weight

Due to closed-cell structure, dense skin (outer and inner), and non-polarity of raw material, Aeroflex has better resistance to water absorption compared to NBR/PVC based insulation

Water Vapor Permeability





Moisture Resistance

0.10 Perm.inch





More than 5000

Each brand has difference water vapor permeability value ranging from 0.10 – 0.30 Perm.inch


Ranges from 1000–7000

Water Vapor Permeability and Moisture Resistant values play an important role in the quality of insulation. If WVP is high – the resulting moisture penetration is also high. Alternately, low WVP will result in low moisture penetration.





Nitrosamine Content

No Nitrosamine found according to US FDA test standard





Most of the rubber insulation has Nitrosamine content ranging from 100 ppb up to 20,000 ppb.





It has been scientifically proven that nitrosamine can cause cancer.

Flammability, Smoke Density and Toxicity

UL94-V0 – PassedASTM E-84 25/50





UL94-V0 – Passed Only few manufacturers of NBR/PVC blend technology have passed ASTM E-84 25/50 fire rating





This standard was created; keeping in mind not only the flames spread but also the smoke density. In most cases of accidental fire, it’s the toxic smoke that causes casualty rather than the fire itself. It has been noted in several proven cases that during accidental fires, the victims fell unconscious due to the toxic smoke, making it hard to save their own lives.

To pass this standard the samples are burnt in a 24-feet long chamber and the flame spread & smoke density are measured, which should be no more than 25 & 50 respectively.

NBR/PVC blends use halogens as their main flame retardants and these halogens create a high percentage of toxic smoke density when burnt, preventing most manufacturers from passing this standard. Additionally, even a small amount of this smoke is considered toxic to human health.


IMO FTP, Annex 1, Part 5 & Part 2





Few manufacturers of rubber insulation have passed Part 5. And Part 2.





IMO stands for International Marine Organization and it’s a fact that more lives are lost on sea due to onboard fire. Keeping this in mind, IMO has created this test where the criteria are to have the least minimum fire spread and lowest level of toxicity. Although Aeroflex test results came fairly on fire rating, the toxicity results were much better than the acceptable criteria.

The few NBR/PVC manufacturers, who opted to test for this particular test, went with Part 5 only. It is to be noted that Part 5 of IMO FTP Code deals with flame spread and does not take into consideration any toxicity or smoke density. On the other hand Part 2 deals with Smoke and Toxicity levels. Due to the intense use of halogen-based flame retardants and toxic raw materials themselves, it is not possible for NBR/PVC products to pass this standard.


References List

1. The United Nation Conference Center, Bangkok Thailand

2. Train Station, TokyoJapan

3. Luth, Kuala Lampur – Malayasia

4. RafflesCity Complex – Singapore

5. SHKTahnoonBuilding, Abu-Dhabi – UAE

6. QueenSirikitNationalConferenceCenter, BangkokThailand

7. BangkokInternationalAirport, BangkokThailand

8. WorldTradeCenter, BeijingChina

9. Ascom HQ – Switzerland

10. WorldTradeCenter, BangkokChina

11. Imperial Queen’s Park Hotel, BangkokThailand

12. Grand Hyatt Erawan Hotel, BangkokThailand

13. Luxury Condominium – Singapore

14. EPF, Kuala Lampur – Malaysia

15. 5,000 Room Ambassador Jomtien Hotel, Pattaya – Thailand

16. P.T.T. HQ, BangkokThailand

Application Methods


1.1    SCOPE 

        The scope of this section comprises the supply and application of insulation conforming to these specifications. 

1.2    MATERIAL 

        Thermal insulation material for Duct & Pipe insulation shall be closed cell Elastomeric EPDM Rubber. The Thermal conductivity of the insulation material shall not exceed 0.038 W/mK at an average temperature of 32oC.  Density of the EPDM rubber shall be 40-60 Kg/m3. The product shall have temperature range of –57 oC to 125oC. The insulation material  shall be  fire rated for Class V 0 as per UL 94.The flammability and smoke density shall be 25/50 as per ASTM E 84, Non-flammable as per JIS K 6911, Australian standard 1530 and class 5.3 as per EMPA.  Water vapour diffusion resistance factor (µ) ≥ 7000.The water absorption (weight %) shall not exceed 5 as per ASTM D 1056. The insulation material should be free from Nitrosamine contents as per US FDA norms. It should be CFC free. It should not be corrosive to copper and stainless when tested as per DIN 1988.The material should not develop crack when tested for ozone resistance as per ASTM 1149. The % shrinkage (Heat Stability) should not exceed 6 when tested as per ASTM C 534( 93oC, 7 days). No cracks should develop when exposed to UV (accelerated weathering resistance test cycle UVB-313 at 60 oC/8h, CON at 50 oC/4h) as per ASTM G 154-04. The resistance to microbiological growth should be in accordance to UL 181 – and meet the acceptance criteria of resistance to fungal contamination as per ASTM G21. It should meet the acceptance criteria of resistance to bacterial contamination as per ASTM 2180.


        Thickness of the insulation shall be as specified for the individual application.  Each lot of insulation material delivered at site shall be accompanied with manufacturer’s test certificate for thermal conductivity values, density, water vapour resistance factor, Nitrosamine content, Heat stability and fire properties.  Samples of insulation material from each lot delivered at site may be selected by Owner’s site representative and gotten tested for thermal conductivity and density at Contractor’s cost.  Adhesive used for sealing the insulation shall be modified neoprene contact adhesive with minimum bond strength of 1.25 kg/m2. It should have high water vapour resistance, good weathering properties and self-extinguishing once dried strictly as per manufacturer’s recommendations.


        Ducting insulation thickness shall be as per table below.


Ducting position

Thk. for non-coastal places

Thk. for coastal places

SA duct in RA path



Ducted return air system

SA duct: 19mm

RA duct: 13mm

SA duct: 25mm

RA duct: 19mm

Both SA& RA exposed

Both 25mm

Both 25mm




        External  thermal  insulation shall be  provided  as follows :       

The thickness of EPDM rubber shall be as shown on drawing or identified in the schedule of quantity.  Following procedure shall be adhered to: 

Duct surfaces shall be cleaned to remove all grease, oil, dirt, etc. prior to carrying out insulation work.  Measurement of surface dimensions shall be taken properly to cut closed cell elastomeric rubber sheets to size with sufficient allowance in dimension.  Cutting of EPDM rubber sheets shall be done with adjustable blade to make 900 cut in thickness of EPDM rubber sheet.  Hacksaw or blades are not acceptable tools for cutting the insulation. 

Material shall be fitted under compression and no stretching of material shall be permitted.  A film of adhesive shall be applied on the back of the insulating material sheet and then on to the metal surface.  When adhesive is tack dry, insulating material sheet shall be placed in position and pressed firmly to achieve a good bond.  All longitudinal and transverse joints shall be sealed by providing 3 mm thick 50 mm wide self-adhesive EPDM insulation foam tape. The density of the EPDM insulation foam tape should be 60 – 80 kg/m3 as per ASTM D 1667. The thermal conductivity of the insulation tape should be 0.04 W/mk at 24oC(As per ASTM C177). The water vapour permeability of the foam tape should be 0.12 perm-inch (as per ASTM C 355). The water absorption of the EPDM rubber foam tape should be max 5% by weight (as per ASTM D 1056). The temperature range of the self-adhesive tape should be -29oC to 93oC and shall be strictly as recommended by the manufacturer. 


        All chilled water, refrigerant, and condensate drain  piping shall  be  insulated in the manner specified  herein. Before applying  insulation,  all pipe shall  be brushed  and cleaned.  All  MS pipes shall be provided with a coat of zinc  chromate primer. Thermal insulation shall be applied as follows or as specified in drawings or schedule of quantity:      

Pipe nominal bore

Thk. for non-coastal places

Thk. for coastal places

15mm – 25mm



32mm – 80mm



100mm – 400mm



Above 400mm



        Insulating material in tube form shall be sleeved on the pipes.  On piping, slit opened tube from insulating material shall be placed over the pipe and adhesive shall be applied as suggested by the manufacturer.  Adhesive must be allowed to tack dry and then press surface firmly together starting from butt end and working towards centre. 

Alternatively factory manufactured pre-slit tubes with self-adhesive pressure sensitive tape applied along the slit surface and covered with 25mm - 50mm wide 0.6mm thick self-adhesive EPDM protective tape overlap longitudinally along the slit should be used. For insulation tubes having OD ≥ 50mm, the protective EPDM tape of 50mm width is recommended.  

Wherever flat sheets shall be used it shall be cut out in correct dimension using correct tools.  Scissors or Hacksaw-blade shall not be allowed. All longitudinal and transverse joints shall be sealed as per manufacturer recommendations. All longitudinal and transverse joints shall be sealed by providing 0.6 mm thick, 50 mm wide self-adhesive EPDM rubber protection tape. The density of the protection tape should be 1.52 ± 3 gm/cm3. The tensile strength of the EPDM protection tape should be more than 2.5N/mm as per JIS K6301. The percentage elongation should be more than 50% as per JIS K 6301(speed 50mm/min).The adhesion peel strength should be more than 0.4 kg/25mm as per ASTM D 3330. The initial tack should be less than 1.5 cm as per ASTM D3121. The adhesive shall be strictly as recommended by the manufacturer. The insulation shall be continuous over the entire run of piping, fittings and valves.  All valves, fittings, joints, strainers etc. in chilled water piping shall be insulated to the same thickness as specified for the main run of piping and application shall be same as above.  Valves bonnet, yokes and spindles shall be insulated in such a manner as not to cause damage to insulation when the valve is used or serviced.  

Manufacturer’s installation manual shall be submitted and followed for full compliance.  All insulation work shall be carried out by skilled workmen specially trained in this kind of work.  All insulated pipes shall be labeled (S.R. or R.R.) and provided with 300 mm wide band of paint along circumference at every 1200 mm for colour coding.  Direction of fluid shall also be marked.  Un-insulated MS pipes shall be painted throughout and direction of fluid marked.  All painting shall be as per relevant BIS codes. 


Floor of data centre shall be insulated with 9mm thick EPDM rubber insulation as per specifications. 750mm x 750mm grid shall be made on the floor. This grid shall be made from 25mm wide 22G GI  C-section. These C-sections shall be screwed to floor. Depth of screwing in to the floor shall not be more than 5mm. Sections of insulation shall be stuck to floor with self-adhesive / adhesive solution as recommended by insulation manufacturer. 


        To provide mechanical strength and protection from damage including UV rays and ozone protection - all pipe / duct insulated with EPDM rubber shall be covered with self-adhesive 0.6mm thick EPDM rubber protective sheet/tape. The tensile strength of the EPDM protection tape should be more than 2.5N/mm as per JIS K6301. The percentage elongation should be more than 50% as per JIS K 6301(speed 50mm/min).The adhesion peel strength should be more than 0.4 kg/25mm as per ASTM D 3330. The initial tack should be less than 1.5 cm as per ASTM D3121. The adhesive shall be strictly as recommended by the manufacturer. 


        Chilled water pump shall be insulated to the same thickness as the pipe to which they are connected and application shall be same as above.  Care shall be taken to apply insulation in a manner as to allow the dismantling of pumps without damaging the insulation. 


        The chiller  shells  shall  be  factory insulated in accordance with the manufacturer’s  standards. 


        Cold  water tank, and chilled   water  expansion tank shall be  insulated as  per manufacturer’s standard. 




        Underdeck insulation shall be 25mm thick EPDM insulation sheet.  Underdeck surface of ceiling shall be cleaned and made dirt free. Insulation sheet shall be pasted on this surface with modified neoprene contact adhesive. 28g wire net shall be tightened around insulation so as to avoid any kind of sagging. Ends of net shall be overlapping by at least 25mm. Overlaps shall be screwed with galvanised screws to avoid rusting. 





Unless    otherwise   specified measurement  for  duct and pipe insulation  for  the  project shall be on the basis  of centre line measurements  described herewith 

a.     Pipe  Insulation shall be measured in units  of  length along the centre line of the installed pipe, strictly  on the  same  basis  as the  piping  measurements  described earlier.  The linear measurements shall be  taken  before the  application of the insulation. It may be noted  that for  piping measurement, all valves, orifice  plates  and strainers are not separately measurable  by their number  and size.  It  is  to  be clearly  understood  that  for  the insulation measurements, all these accessories  including cladding,  valves, orifice plates and strainers shall  be considered  strictly  by linear  measurements  along  the centre  line  of  pipes  and no  special  rate  shall  be applicable for insulation of any accessories, fixtures or fittings whatsoever. 

b.     Duct  Insulation and Acoustic Lining shall be  measured on  the  basis of surface area along the centre  line  of insulation thickness. Thus the surface area of externally thermally  insulated or acoustically lined  be based  on  the  perimeter  comprising  centre  line   (of thickness  of  insulation) width and depth of  the  cross section  of  insulated or lined duct, multiplied  by  the centre-line length including tapered pieces, bends, tees, branches, etc. as measured for bare ducting.  


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