May 20, 2014

POLYURETHANE FOAM 

INSULATION TECHNOLOGIES

BLOWING AGENTS UPDATE
Agenda

 Administrative Items

 EPA SNAP Staff Remarks

 Polyurethane (PU) Foam Insulation Technologies

 General Overview of Applicable Building Codes & Standards

 Steps for Identifying Potential Substitute Blowing Agents

 Life-Cycle Assessment and Insulation Technologies

 Other Items
Intro to 

Polyurethane 

Foam 

Insulation 

Technologies

 Unique Role of Blowing 

Agents in PU Foam Insulation 

Technologies 

 Types of Polyurethane Foam 

Insulation Technologies
Chemical vs Physical BA

Chemical Blowing Agents (BA) for PU Foams

Chemical conversion creates gaseous byproduct:

MDI (A side) + Water (B side)  CO2 gas

Common process for all flexible PU foams, as well as opencell, low density SPF. 

100% CO2is not practical for closed-cell foams due to high 

thermal conductivity, high diffusion and dimensional 

stability problems.
Chemical vs Physical BA (cont.)

Physical Blowing Agents for Spray Polyurethane Foam

High molecular weight (MW) (compared to CO2), low 

diffusion rate and low thermal conductivity  fluorinebased molecules

High-Pressure SPF: Liquid phase at room temperature and 

pressure, changes to gaseous phase by heat from 

exothermic polymerization reaction

Low-Pressure SPF: Gaseous phase at room temperature 

(under pressure) expands when pressure is released and 

aided by exothermic reaction
Chemical vs Physical BA (cont.)

Physical Blowing Agents for PU Foams

High MW = low diffusion rate and low thermal conductivity 

 Fluorine based

“Liquid” Blowing Agents: Liquid phase at close to room 

temperature and pressure; become volatilized by heat from 

exothermic polymerization reaction

Low-Boiling Blowing Agents (LBBAs): Gaseous phase at 

room temperature (under pressure); expand when pressure 

is released and aided by exothermic reaction
Polyurethane Foam Insulation 

Technologies

 PIR Board/Bunstock

 Appliance

 Metal Panel

 High-Pressure Two Component

 Closed-cell

 Open-cell

 Low-Pressure Two Component

 One Component Foam

factory made

field applied
Spray Polyurethane Foam 

Insulation Technologies 

One Component 

Foam

Low-Pressure

Two Component

High-Pressure

Two Component

• A and B side mixed >> pre-polymer

• Moisture cure 3-20 min

• Bead application for air sealing/firestop

• DIY and weatherization

• A and B side in separate pressurized 

cylinders (<250 psi)

• No pre-heating of chemicals

• Mechanical mixing of A and B at nozzle

• Chemical cure <1 min

• Bead application and small area 

insulation/repair

• Weatherization and professional use

• A and B side in separate unpressurized 

drums or totes

• Chemicals are preheated (~130F) and 

pressurized (~1200 psi) using special 

equipment

• Aerosolized chemicals > impingement mix

• Chemical cure <15 seconds

• Large area insulation and roofing

• Professional use only
Regulatory Evolution (US)

PU Foams (factory) Spray Polyurethane Foams (field) Key Properties

Name PIR Board/ 

Bunstock Appliance Metal Panels HP-SPF LP-SPF two-component

OCF - one

component foam

ODP 

(CFC eq)

GWP(1) 

(CO2 eq)

lambda 

(W/m°K)

boiling 

point (°C) flammable

Generation 1 

CFC-11     1 4660 0.01 23.7 no

CFC-12   1 10200 0.011 -29.8 no

Generation 2 

HCFC-141b     0.11 782 0.010 32.2 no

HCFC-142b 0.065 1980 0.013 -9.8 no

HCFC-22    0.055 1760 0.011 -40.8 no

Generation 3

HFC-245fa    0 858 0.013 15.3 no

HFC-365mfc  (2) 0 804 0.011 40.2 yes

HFC-134a   0 1300 0.014 -26.2 no

Generation 4 

HFO-1233zd  under devl. under devl. 0 1 0.010 19 no

HFO-1336mzz-Z under devl. under devl. under devl. 0 2 0.011 33 no

HFO-1234ze under devl.(3)  0 <1 0.010 -19 no

Other Options

pentanes    0 <25 0.015 49 YES(4)

CO2 (from water)  Gen 3 additive 0 1 0.087(5) -71 no

methyl formate Gen 3 additive(6) 0 <25 0.0107 31.5 YES

(1) IPCC 5th Assessment Report 2013

(2) Beginning January 2013; often blended with HFC-227ea

(3) Challenges with extended shelf-life for two-component low-pressure SPF

(4) High flammability poses safety hazard for field applied products like HP-SPF and LP-SPF

(5) Rapidly diffuses from within closed-cell foam without diffusion barrier (e.g., metal facings) resulting in low R-value and dimensional stability issues (shrinkage)

(6) Not a stand-alone blowing agent for HP-SPF; typically blended with other blowing agents to reduce 

flammability
Regulatory Evolution (US) (cont.)
Considerations for SPF 

Blowing Agents

There are many factors to consider when selecting 

blowing agent for Spray Polyurethane Foams

• Boiling Point below → just above room temp (RT) (for HP SPF)

• Boiling Point well below RT for LP SPF

• Remains chemically stable in one and two-component systems

• Soluble with all raw materials

• Partially soluble in LP SPF

• Low-solubility in final polymer foam (reduce thermal drift) 

• Provides good thermal properties (low lambda)

• Environmentally benign (low ODP, GWP)

• Non flammable (important for field applied foam)
Overview of 

Application 

Building Codes 

& Standards 

(US)

 U.S. Model Building Codes

 Evaluation Reports

 Material Performance
US Model Building Codes

International Code Council (ICC) Code Sections

– Separate from „traditional‟ insulations

– IBC: Ch 26, Section 2603 Foam Plastic Insulation

– IRC: Ch 3, R316 Foamed Plastic

Code Focus

– Fire Protection

– Thermal Performance

– Moisture Control
Evaluation Reports

ICC Evaluation Services Acceptance 

Criteria AC-377

– Provides guidance for creating Evaluation 

Service Reports (ESRs)

– ESRs assure product compliance with 

specific versions of the building code

– Defines mandatory and option testing and 

performance requirements for SPF 

insulation

– Requires 3rd party oversight of 

manufacturing process
SPF Performance Tests

ASTM Test Sealant Low

Density

Med.

Density Roof

PERFORMANCE

Thermal Resistivity (R/in) C518, C1363 

C1303, C177 N/A 3.6 - 4.5 6.2 - 6.8 6.2 - 6.8

 Air Impermeable E283, E2178 * > 3.5-5.5” > 1” > 1”

 Vapor Retarder E96 1 perm > 2” 1 perm > 2”

 Surface Burning (FSI/SDI) E84 75/450 75/450 75/450 75/no limit

 Room Corner Fire Test NFPA 286, 

UL1715, FM4880 TB > 4” > 4”

 “Appendix X” Test Mod NFPA 286 IB IB IB

 Dimensional Stability D2126 < 15% < 9-12% < 5-6%

 Water Resistance D2842  

 Fungi Resistance C1338  

 Compressive Strength C165 >15 psi > 40 psi

 Tensile Strength D1623 > 20 psi > 42 psi

Four categories of SPF for 

construction applications
Identifying 

Potential 

Substitute 

Blowing Agents 

for Spray 

Polyurethane 

Foam Insulations 

 Discussion Regarding 

Commercially Available 

Substitutes

 Research and Development 

Consideration

 Field Testing Considerations

 Building Codes & Standards 

Testing
Development of New BA

Blowing Agent Suppliers

• Use a generic foam formulation to determine compatibility and 

functionality

• Perform wide range of chemical safety, toxicity and 

environmental testing (SDS development, EPA-TSCA PreManufacturing Notice, REACH compliance, etc.)

• Modification or construction of production facilities

• 6-8 year development cycle for BA manufacturers

• Development (not use) of 4

th Generation BA for PU is nearing 

completion 
Integration of New BA for SPF

SPF Systems Houses

• Each foam suppliers formulation is different; new blowing agents 

are never „drop in,‟ and require re-formulation of the B-side

• B-side reformulation involves several, often iterative, steps: 

• Lab evaluation and product design 

• Field evaluation for spray-ability in different seasons and climates

• New set of material property tests 

• Re-issuance of the ESR

• 3-5 year integration cycle is typical for SPF systems houses

• Can overlap with end of BA supplier development cycle

• Some US HP-SPF systems houses are beginning to research use of 

4

th generation BA
Integration of New BA for SPF (cont.)

Low Pressure SPF Systems Houses

• Each foam suppliers formulation is different; new blowing agents 

are never „drop in,‟ require re-formulation of the B-side

• B-side reformulation involves iterative steps (like HP SPF)

• 3 - 4 year integration cycle is typical for LP SPF systems houses

• Major delay with integration of low-GWP BA in two-component foam is 

shelf life stability caused by chemical interactions between BA and some 

catalysts.

• LP systems houses are having significant technical issues with low-GWP 

blowing agents and no clear path to a solution has yet been identified --

data available for EPA SNAP review.

• No US LP systems houses currently using low-GWP BA in twocomponent foam. However, one-component foam with low-GWP 

is commercially available.
Life-Cycle 

Assessment 

and Insulation 

Technologies

 LCA Considerations for 

Energy Efficiency 

Technologies

 SPF Industry LCA and 

Environmental Product 

Declaration (EPD)

 Next Generation Low 

GWP Blowing Agents
LCA Considerations for Energy 

Efficiency Technologies

“Solely using GWP as selection criteria for foam 

blowing agents could lead to the selection of 

alternative technologies that provide a reduced 

R-value and over time would result in more GHG 

emissions than would be emitted from the foam 

insulation itself.” 

– Alliance for Responsible Atmospheric Policy
SPF Industry LCA and EPD

• SPF, like all building materials, has an 

environmental impact from production, 

transportation, installation and disposal 

• Energy savings from insulating and air sealing 

buildings with SPF can recover negative impacts 

within a short time

• An ISO-compliant, third-party Life Cycle Assessment 

(LCA) and Environmental Product Declaration (EPD) 

by the Spray Polyurethane Foam Alliance (SPFA) for 

LD, MD and Roofing SPF materials

Copies of the full SPFA LCA and EPD report may be downloaded from 

www.sprayfoam.org

This report details the known environmental impacts of SPF on primary energy, 

global warming, smog creation, acidification, eutrophication and ozone depletion.

Long-Term Environmental Impacts
SPF Industry LCA and EPD

Total GWP per Functional Unit of SPF

• Impact from End-of-Life, Use-Phase and Installation directly 

affected by GWP from BA

• BA contributes GWP to Raw Materials and Blending
SPF Industry LCA and EPD1

Application SPF Type Ratio & Payback Houston Richmond Minneapolis

Energy GHG Energy GHG Energy GHG

Residential Insulation Low Density OpenCellAvoided/Embodied 64 92 128 164 194 248

Payback (Yr) 0.9 0.7 0.5 0.4 0.3 0.2

Medium Density 

Closed-Cell

Avoided/Embodied 32 7.6 64 13.6 98 21

Payback (Yr) 1.9 7.9 0.9 4.4 0.6 2.9

Commercial Roofing Roofing

R4 --> R20

Avoided/Embodied 55 15 56 15 66 17

Payback (Yr) 1.1 4 1.1 4.1 0.9 3.6

Roofing

R12 --> R20

Avoided/Embodied 30 8.2 28 7.5 29 7.3

Payback (Yr) 2 7.3 2.1 8.0 2.1 8.3

Use-Phase Analysis for Generation 3 HFC BA

• 3-8 year return for MD-SPF

• 4 year return for Roofing SPF Anticipated service life of 

these products is 60+ years

1. For additional information and definitions, please download the full SPFA LCA and EPD reports from 

www.sprayfoam.org. 
Impact of Next Generation BA for SPF

Product-Level LCA Available for HFO BA

• ~1000x reduction in GWP for HFO vs. HFC molecules

• Both Liquid and Gas BA‟s

• Honeywell: Analysis shows a significant decrease of GWP in 

finished SPF when low-GWP blowing agents are used. 

• 25-35 kg CO2 eq. for HFC-245fa-blown SPF

• 4 kg CO2 eq. for HFO-1233zd(E) blown SPF

• DuPont: Analysis shows a significant decrease in both Direct 

(>99%) and Indirect (Up to 12% in multiple foam uses) Climate 

Change Potential (CCP)

• Arkema
Other Items  Question & Answer

 Additional Information 

Needs