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MONTREAL PROTOCOL 

ON SUBSTANCES THAT DEPLETE 

THE OZONE LAYER 

 

 

UNEP 

 

2014 REPORT OF THE 

RIGID AND FLEXIBLE FOAMS TECHNICAL 

OPTIONS COMMITTEE 

 

2014 ASSESSMENT REPORT
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UNEP

REPORT OF THE

RIGID AND FLEXIBLE FOAMS TECHNICAL OPTIONS COMMITTEE

2014 ASSESSMENT REPORT

Published March 2015

ISBN: 978-9966-076-10-6
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Contents

1. Key Messages..............................................................................................................................5

2. Executive Summary.....................................................................................................................6

Trends in Global Foam Use and Impacts on Blowing Agent Consumption.....................................6

Overview of Progress and Challenges related to Blowing Agent Transitions.................................7

Update on Bank Estimates and Emerging Management Strategies...............................................8

3. Trends in Global Foam Use and impacts on Blowing Agent Consumption...............................10

Growth in Global Foam Use..........................................................................................................10

Impact on Blowing Agent Consumption .......................................................................................11

Projection of Business-as-Usual Trends to 2020...........................................................................11

4. Overview of Progress and Challenges Related to Blowing Agent Transitions..........................12

Progress with HCFC Phase-out Management Plans (HPMPs) in the Foam Sector .......................12

Particular Challenges with PU Spray Foams and Extruded Polystyrene.......................................12

Enterprise Size and Economies of Scale........................................................................................14

Drivers for reducing Saturated HFC use in Non-Article 5 Parties .................................................14

Summary .......................................................................................................................................14

5. Low-GWP Alternatives by type and their significance in the Foam Sector ..............................15

Broadening acceptance of Hydrocarbons.....................................................................................15

Carbon Dioxide as a blowing agent...............................................................................................16

Latest Status of Unsaturated HFC/HCFC Developments...............................................................16

Progress with other Low GWP Alternative Blowing Agents .........................................................17

6. Review of blowing agent selection by foam sub-sector and region.........................................18

Polyurethane Foams in the Refrigeration Sector..........................................................................18

Polyurethane Boardstock..............................................................................................................21

Polyurethane Panels.....................................................................................................................24

Polyurethane Spray.......................................................................................................................26

Polyurethane In-situ/Block ...........................................................................................................29

Polyurethane Integral Skin............................................................................................................31

Extruded Polystyrene Foam..........................................................................................................34

Phenolic Foam...............................................................................................................................36

7. Update on Bank Estimates and Emerging Management Strategies.........................................39

Estimated size of current Blowing Agent Banks and predicted growth to 2020 ..........................39

Identifying Blowing Agents in the Waste Stream and other Waste Management challenges.....39

Assigning value to Blowing Agent recovery and likely impact on trends going forward..............39

Best Practice in the management of Insulation Foams and the importance of Segregation.......40

8. Membership of the Foams Technical Options Committee.......................................................42
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1. Key Messages 

 Growth in the construction sector in Article 5 parties, coupled with the adoption of 

enhanced energy efficiency criteria for buildings has led to a growth in demand for thermal 

insulation materials in these regions

 Insulation foams have been the material of choice, although concerns over flammability 

have hindered adoption in some key markets, particularly where construction methods 

expose hazards. Differentiation between product types is increasingly occurring

 In non-Article 5 parties, an increasing focus for insulation use has been in existing buildings, 

where solutions are required to be both efficient and cost-effective. PU Spray foam has 

made considerable inroads as a result. 

 Global blowing agent consumption is estimated to have reached approximately 390,000 

tonnes annually in 2014 and is expected to continue to grow at around 4.8% per year 

through to 2020, leading to an overall consumption in excess of 520,000 tonnes with 

hydrocarbons representing over 50% of the total.

 The enactment of Decision XIX/6 has been the major driver for blowing agent transitions 

since 2010, although the implementation of Stage 1 of HCFC Phase-out Management Plans 

(HPMPs) has been hampered in some regions by administrative procedures. 

 The focus of HCFC phase-out in the foam sector to date has been HCFC-141b based on the 

“worst-first” principle. However, this has led to a significant tail of HCFC-142b/22 use in the 

XPS sector which has continued to grow rapidly since 2010, particularly in Asia. 

 There is some evidence to suggest that the XPS growth may have caused a nominal ‘breach’ 

in the 2013 freeze for Article 5 parties when taking the foam sector in isolation. However, 

this is unlikely to show at the reporting level because of potential counter-balances within 

other sectors of HCFC use. 

 HFOs continue to be evaluated within the foam sector and are showing considerable 

promise, particularly as a result of their contributions to thermal efficiency even at relatively 

low levels within formulations. One manufacturer is already producing commercially with 

others likely to follow within the next two years. Ultimate system costs remain uncertain, as 

does the geographic availability of those HFOs still to be fully commercialised. 

 The challenge of dealing with a multitude of SMEs in both Article 5 and non-Article 5 parties 

remains. Lack of economies of scale prevents the investment in flammable solutions, leaving 

high GWP solutions as the only option, often with considerable emissions. 

 Oxygenated hydrocarbons such as methyl formate and methylal are being increasingly used

in Article 5 parties, especially in integral skin applications, although flammability remains an 

issue to be managed. There are also some minor HFO stability issues to be resolved in some 

low pressure PU Spray formulations. 

 Banks of blowing agents are expected to exceed 5 million tonnes, inclusive of hydrocarbons 

by 2020. Much of the ODS component of these banks will already be in the waste stream by 

then as products with more limited lifecycles (e.g. appliances) reach end of life. 

 Based on the climate benefit accruing from recovery, the average global warming potential 

of blowing agents in the waste stream will only further decline over the period through to 

2020 making the economic justification for recovery more challenging.
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2. Executive Summary 

Trends in Global Foam Use and Impacts on Blowing Agent Consumption

The global economic recession of 2008/9 has had some significant impact on investment within the 

construction sector since 2010, particularly in non-Article 5 parties. Project lead times associated 

with new-build projects (typically 2-3 years from initiation to completion) have meant that recovery 

of activities has only really surfaced in 2012/13. However, investment in new construction in Article 

5 parties has continued broadly unabated. Building renovation projects in Europe have been less 

affected by the downturn, partly because their lead times are shorter and partly because the 

investments are lower in magnitude. There is also recognition that, in most non-Article 5 parties, 

over 50% of the buildings that will be operational in 2050 have already been built. If progress on 

building energy efficiency and related CO2 emissions is going to be made, then significant renovation 

will be necessary. 

In all buildings, the demand for thermal insulation has increased substantially as their role in 

reducing energy dependency and greenhouse gas emissions has been recognised. New or improved 

thermal insulation requirements have emerged across the Middle East and throughout India, China, 

South Africa and Latin America. Even though there has been some shift between fibre and foam 

market shares in China during the period, mostly as a result of fire concerns, the production of 

polyurethane chemicals had grown globally to just under 18 million tonnes by 2014. Of this total 

production, an estimated 9.7 million tonnes is consumed in the foam sector annually with 

approximately 5.9 million tonnes being in rigid insulation foam, where it consumes blowing agents of 

interest to the Montreal Protocol. Other competing foam insulation materials are expanded 

polystyrene (never used ozone depleting substances), extruded polystyrene (XPS), phenolic and 

polyethylene foams. XPS foams are understood to consume about 1.25 million tonnes of polystyrene 

globally. Based on average blowing agent percentages of 5.5% w/w for polyurethane and 4.5% w/w 

for XPS, this leads to an estimated demand of approximately 380,000 tonnes between them with a 

further 10,000 tonnes being consumed by other foam types.

Current foam projections1predict on-going growth to 2019 of 4.8% per year, compared with 4.4% 

per year for 2009-2014. On this basis global blowing agent consumption will exceed 520,000 tonnes 

by 2020 unless there are further gains in blowing efficiency as technologies develop. Based on these 

trends, the historic, current and future demand for physical blowing agents is summarised in Figure 

ES-1 below:

 Source: FTOC 

Figure ES-1: Growth in the use of Physical Blowing Agents by Type over the period from 1990 to 2020

 

1

RAPRA Report ‘The Future of Polymer Foams: Market Forecasts to 2019’ 
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Overview of Progress and Challenges related to Blowing Agent Transitions 

The major blowing agent transitions being driven by regulation currently are those in Article 5 

parties resulting from Decision XIX/6 and being funded under national HCFC Phase-out Management 

Plans (HPMPs). First phase HPMP implementation is generally running smoothly, although there 

have been delays in the initiation of some plans owing to the significant administration involved. 

Since Decision XIX/6 requires a “worst first” approach, the phase-out of HCFC-141b has been 

particularly targeted over the period covered by this report. This has been broadly successful within 

larger enterprises where the critical mass of the operation is sufficient to justify investment in 

hydrocarbon technologies, often with individual enterprises being willing to co-fund the investment 

where the funding thresholds available under the Multilateral Fund have been insufficient. 

Foams manufactured using other blowing agents, notably extruded polystyrene (XPS), have not 

typically been part of the first phase of most HPMPs. This is because there are no proven low-GWP 

alternatives to HCFC-142b/22 currently available. Although CO2 technology is prevalent in Europe, it 

is still not clear whether it is sufficiently versatile for the variety of manufacturing plants operating in 

Article 5 parties. Other alternatives include hydrocarbons and ethers, but the flammability of these 

blowing agents is problematic when coupled with polystyrene itself which is also facing 

reformulation of brominated flame retardants. The situation has been further compounded in Asia 

since 2010 by a series of significant fires associated with insulation which have taken place during 

the construction phase of some high-rise buildings. Despite these concerns, investment in XPS 

manufacturing capacity has spiralled in response to increased demand for inexpensive and effective 

insulation. This has particularly been the case in Russia, the Middle East and parts of Eastern Europe 

and North Africa. The current choice of blowing agent in these regions are blends of HFC-134a/HFC152a - not ideal for the climate, since these have relatively high GWP and the manufacturing process 

is typically quite emissive. There may be some hope that blends based on a combination of hydro 

fluoro olefins (HFOs) and/or hydro chloro fluoro olefins (HCFOs) together with hydrocarbons or 

ethers may ultimately satisfy the process and product requirements of XPS, but the continuing 

uncertainty is causing delay on conversions under relevant HPMPs. The net impact of these trends is 

projected in the Figure ES-2 below: 

Figure ES-2: Evolution of consumption patterns for blowing agents in Article 5 Parties with time
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The growth in XPS can be seen as potentially responsible for a breach of the 2013 Freeze – at least 

for the foams sector. However, this does not automatically mean that parties will be non-compliant 

with the Protocol, since there is always the potential to compensate in other sectors. 

The other major factor that threatens the smooth phase-out of blowing agents is dealing with the 

challenge of small medium enterprises (SMEs). Lack of economies of scale prevents the adoption of 

hydrocarbons, while the adoption of high GWP alternatives results in high climate impact within 

processes which are typically less well engineered or are unavoidably emissive. Although transitions 

from HCFCs to HFCs were largely unavoidable in many non-Article 5 parties during phase-out of 

HCFCs, there is increasing pressure to switch to low-GWP technologies. In view of hydrocarbon 

flammability, the focus is on the potential role of less flammable blowing agents such as 

HFOs/HCFOs or all water-blown formulations. For integral skin, oxygenated hydrocarbons such as 

methyl formate and methylal are becoming the blowing agent of choice while the major PU Spray 

Foam markets of the USA and Canada, look likely to adopt HFOs/HCFOs, with commercial systems 

now beginning to emerge. 

Non-Article 5 parties in North America, Europe and Japan are now pursuing regulatory strategies to 

encourage the phase-out of HFC use in the foam sector. In Europe, this has been enacted under the 

re-cast F-Gas Regulation, while in the USA, the existing Significant New Alternatives Program (SNAP) 

is being explored as a tool for the de-selection of some blowing agent options. These regulatory 

initiatives could place particular pressure on the XPS industry in these regions, since universally 

acceptable alternatives are still to emerge. In Japan, GWP limits have been set on PU Spray foam 

from 2020 and reporting requirements continue for HFC-245fa and HFC-365mfc.

Update on Bank Estimates and Emerging Management Strategies 

Global banks of blowing agents in foams are estimated to have grown from around 3 million tonnes 

in 2002 to an estimated 4.45 million tonnes in 20152. Based on current consumption estimates, 

these will grow to well in excess of 5 million tonnes by 2020. However, a significant proportion of 

this bank will already have moved into the waste stream (typically landfill) by then. To deter this, 

ODS-containing foam is being increasingly treated as hazardous waste, but policing shipments is 

difficult when no simple way of determining foam blowing agent exists. The search for appropriate 

detection equipment continues for both the characterisation of waste and the monitoring of crossborder trade. A further option is to encourage voluntary intervention at decommissioning by 

assigning value to the process. Although climate benefits are the focus, the average global warming 

potential (GWP) of the waste stream will decrease with time as the average GWP decreases. Figure 

ES-3 illustrates this trend: 

 

2

Data adapted from Special Report on Ozone and Climate (2005) – values include hydrocarbons
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 Figure ES-3: Expected decline in average GWP of the waste streams for typical foam applications 

These trends imply that there is an urgent need to introduce effective waste management practices. 

Indeed, much of the climate benefit arising from appliances foams has already passed. This is being 

borne out in practice for many appliance recycling plants, where the associated climate benefit 

cannot now be relied upon as a justification for investment. As a result contractors are looking to 

minimise their upfront investment costs by adopting manual dismantling practices, even though 

there are associated emissions. This is especially the case in areas of low population density, where 

the economies of scale are more limited. 
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3. Trends in Global Foam Use and impacts on Blowing Agent Consumption 

Growth in Global Foam Use

The global economic recession of 2008/9 has had some significant impact on investment within the 

construction sector since 2010, particularly in non-Article 5 parties. The project lead times 

associated with new-build construction projects (typically 2-3 years from initiation to completion) 

has meant that recovery of new construction activities has only really surfaced in 2012/13. However, 

investment in new construction in Article 5 countries has continued broadly unabated. This is 

indicated in the Figure 1 below: 

Source: IHS Global Insight

Figure 1: Growth in Construction Spending 2010/11 vs 2012/13 (%)

Building renovation projects in Europe have been less affected during the period, partly because 

their lead times are shorter and partly because the investments are lower in magnitude. Typically, 

Article 5 parties are focused primarily in new construction, while non-Article 5 parties are 

increasingly turning to renovation strategies. This is partly a recognition that, in most non-Article 5 

parties, over 50% of the buildings that will be operational in 2050 have already been built. If impacts 

on building energy efficiency and related CO2 emissions are going to be made, then significant 

renovation programmes will be required. 

In both new construction and renovation, the demand for thermal insulation has increased 

substantially as the role of buildings in reducing energy dependency and greenhouse gas emissions 

has been recognised. New or improved thermal insulation requirements have emerged across the 

Middle East and throughout India, China, South Africa and Latin America. Although there has been 

some shifting between fibre and foam market shares in China during the period, partially as a result 

of a temporary moratorium3on the installation organic insulation materials (including polyurethane 

and polystyrene) arising from fire concerns, the production of polyurethane chemicals globally has 

grown by 8.8% over the same time period to just under 18 million tonnes. Figure 2 illustrates the 

geographic spread of this production and indicates the growing importance of Article 5 regions in 

both the production and consumption of polyurethane chemicals. 

 

3

Rescinded in December 2012
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Source: PU Magazine 

Figure 2: Regional Distribution of PU Chemical Production in 2012 (~18 million tonnes)

Impact on Blowing Agent Consumption

Of the total polyurethane production, 9.7 million tonnes is estimated to be consumed in the foam 

sector annually with approximately 5.9 million tonnes being in the rigid insulation foam sector, 

where it consumes blowing agents of interest to the Montreal Protocol. Other competing foam 

insulation materials are Expanded Polystyrene (never used ozone depleting substances), Extruded 

Polystyrene (XPS), phenolic and polyethylene foams. XPS foams are understood to consume 

approximately 1.25 million tonnes of polystyrene globally. Based on average blowing agent 

percentages of 5.5% w/w for polyurethane and 4.5% w/w for XPS, this leads to an estimated 

demand of approximately 380,000 tonnes between them with a further 10,000 tonnes being 

consumed by other foam types. 

Projection of Business-as-Usual Trends to 2020 

Current polymer foam projections4suggest on-going growth to 2019 of an average of 4.8% per year, 

which is slightly more rapid than the 4.4% per year achieved in the period 2009-2014. On this basis 

global blowing agent consumption can expect to exceed 520,000 tonnes by 2020 unless there are 

further gains in blowing efficiency as technologies develop. Based on trends in blowing agent 

selection monitored by the Foams Technical Options Committee, the historic, current a future 

demand for physical blowing agents is summarised in Figure 3 below:

 

4

RAPRA Report ‘The Future of Polymer Foams: Market Forecasts to 2019’ 
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Source: FTOC

Figure 3: Growth in the use of Physical Blowing Agents by Type over the period from 1990 to 2020

4. Overview of Progress and Challenges Related to Blowing Agent Transitions 

Progress with HCFC Phase-out Management Plans (HPMPs) in the Foam Sector 

The major blowing agent transitions being driven by regulation at present are those in Article 5 

parties resulting from the enactment of Decision XIX/6 and being funded under a series of national 

HCFC Phase-out Management Plans (HPMPs). HPMPs are currently in their first phase and 

implementation is generally running smoothly, although there have been delays in the initiation of 

some plans owing to the significant administration involved. Since Decision XIX/6 requires a “worst 

first” approach, the phase-out of HCFC-141b has particularly been targeted over the period covered 

by this report. This has been largely successful within larger enterprises where the critical mass of 

the operation is sufficient to justify investment in hydrocarbon technologies. Indeed, in several 

instances, individual enterprises have been willing to co-fund the investment where the funding 

thresholds available under the Multilateral Fund have been insufficient, despite the economies of 

scale. 

Particular Challenges with PU Spray Foams and Extruded Polystyrene

For PU Spray foam the major challenge relates to the safe processing of these systems under in-situ 

conditions within a building. The potential for the accumulation of blowing agent in ‘pockets’ creates 

the risk of fire or explosion if flammable materials are used. Therefore, hydrocarbons have broadly 

been ruled out for these applications. This has led to the retention of HCFC-141b as a blowing agent 
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in Article 5 parties, while formulators and contractors have switched to high-GWP HFCs such as HFC245fa and HFC-365mfc/227ea in non-Article 5 parties, where HCFCs have already been phased out. 

Foams manufactured using other blowing agents, notably extruded polystyrene (XPS) which uses 

HCFC-142b, HCFC-22 or blends thereof, have not typically been part of the first phase of most 

HPMPs. Apart from the fact that the ozone depletion potentials (ODPs) of the blowing agents are 

lower than for HCFC-141b, there are no obvious alternatives currently available. Although CO2 

technology is prevalent in Europe, it is still not clear whether this will be sufficiently versatile to be 

used in the variety of manufacturing plants operating in Article 5 parties. Other alternatives include 

hydrocarbons and ethers, but the flammability of these blowing agents is viewed by many as 

problematic when coupled with a polystyrene matrix which is also facing reformulation of flame 

retardants following the action being taken on hexa-bromo-cyclo-dodecane (HBCD) under the 

Stockholm Convention. The situation has been further compounded in Asia since 2010 by a series of 

significant fires associated with insulation which have taken place in high-rise buildings (typically 

during the construction phase). Despite these concerns, investment in XPS manufacturing capacity 

has continued to spiral as demand for inexpensive and effective insulation has increased. This has 

particularly been the case in Russia, the Middle East and parts of Eastern Europe and North Africa. 

The current choice of blowing agent for these new installations, as well as for the existing ones, are 

blends of HFC-134a/HFC-152a. This is not an ideal choice for the climate, since these blends have 

relatively high Global Warming Potential (GWP) and the manufacturing process for XPS is relatively 

emissive. There may be some hope that blends based on a combination of hydro fluoro olefins 

(HFOs) and/or hydro chloro fluoro olefins (HCFOs) together with hydrocarbons or ethers may 

ultimately satisfy the process and product requirements of XPS, but the continuing uncertainty is 

certainly causing delay on conversions under relevant HPMPs. The net impact of these trends is 

projected in the Figure 4 below: 

Figure 4: Evolution of consumption patterns for blowing agents in Article 5 Parties with time
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The growth in XPS can be seen as potentially responsible for a breach of the 2013 Freeze – at least 

for the foams sector. However, this does not automatically mean that parties will be non-compliant 

with the Protocol, since there is always the potential to compensate in other sectors. Nevertheless, 

the significance of the XPS challenge is self-evident. 

Enterprise Size and Economies of Scale

The other major factor that threatens the smooth phase-out of blowing agents in both Article 5 and 

non-Article 5 parties is the challenge of dealing with a multitude of small medium enterprises 

(SMEs). In these instances, the lack of economies of scale does not allow for the adoption of 

hydrocarbons, while the adoption of high GWP alternatives such as HFCs will result in high levels of 

emission within processes which are either less well engineered or are unavoidably emissive 

because they are used in-situ (e.g. PU Spray Foams). Although transitions from HCFCs to HFCs were 

largely unavoidable in many non-Article 5 jurisdictions at the time of phase-out of HCFCs, there is 

increasing pressure now to switch to low-GWP technologies. With hydrocarbons being problematic 

from a safety perspective, the focus is on the potential role of less flammable blowing agents such as 

HFOs/HCFOs or all water-blown formulations. In some specific market niches such as integral skin, 

oxygenated hydrocarbons such as methyl formate and methylal are becoming the blowing agent of 

choice. In the major PU Spray Foam markets of the USA and Canada, there are increasing signs that 

HFOs/HCFOs may have a significant role to play, with commercial systems now beginning to emerge. 

Drivers for reducing Saturated HFC use in Non-Article 5 Parties 

Non-Article 5 parties in North America, Europe and Japan are now actively pursuing regulatory 

strategies to encourage the phase-out of HFC use in the foam sector, wherever possible. In Europe, 

this has been enacted under the re-cast F-Gas Regulation, while in the USA, the potential to utilise 

the existing Significant New Alternatives Program (SNAP) is being explored as a tool for the deselection of some blowing agent options. These regulatory initiatives could place particular pressure 

on the XPS industry in these regions, since universally acceptable alternatives are still to emerge. 

Summary 

In summary, while HCFC phase-out and HFC avoidance are being pursued in tandem, the more 

challenging areas are yet to be fully tackled. Much still depends on the future availability and cost of 

low-GWP blowing agents. One encouraging factor, particularly with HFOs/HCFOs, is that the thermal 

performance of the foams is, as a minimum, retained and in many cases improved over the HCFCs 

and HFCs that they are likely to replace. The commercialisation plans for these blowing agents 

remain on track and the next 2-3 years should confirm acceptability within the various foam sectors. 
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5. Low-GWP Alternatives by type and their significance in the Foam Sector

Broadening acceptance of Hydrocarbons 

The availability of hydrocarbons at an early stage of the transition from CFCs has made it that a 

genuine low-GWP and cost-effective alternative has been available for large parts of the foam sector 

throughout that period, even at the time of the phase-out of CFCs in non-Article 5 Parties. Therefore, 

the account of the transition history since 1987 in the polyurethane and phenolic product sectors is 

dominated by whether a specific foam sub-sector could adopt hydrocarbon technologies or not. 

There have been a number of reasons cited over the period to explain why hydrocarbon solutions 

were not appropriate. These have included:

 The flammability risks associated with the production/deposition process

 The flammability risks associated with product installation and use

 The higher gaseous thermal conductivity leading to poorer thermal efficiency of the foam

 The cost of flame-proofing measures for production processes in relation to the size of the 

manufacturing plant (lack of economies of scale) 

 Local health & safety regulations

 Local regulations on volatile organic compounds (VOCs) 

 Waste management issues

Some of these have largely been discounted in more recent times, but others continue to be of 

importance and some are even growing in significance (e.g. waste management issues) as 

hydrocarbon blown foams reach end-of-life. Nevertheless, the market penetration of hydrocarbon 

technologies has had a substantial impact as shown in Figure 5 below:

Figure 5: Evolution of market share of foam sector met by hydrocarbons

The slight stall in the growth of market share in hydrocarbon blowing agent in the period 2008-2010 

has occurred as a result of growth in non-dependent foam types such as extruded polystyrene. 
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However, hydrocarbons are still expected to play an increasing role in the period to 2020 as means 

are found to cost-effectively engineer hydrocarbon solutions for medium-sized enterprises. 

The dominance of the hydrocarbon technologies is even greater than it appears from the graph, 

since the blowing efficiency of hydrocarbon blowing agents is considerably better than the CFCs and 

HCFCs that were replaced. This means that the amount of foam blown by the 290,000-295,000

tonnes of hydrocarbons predicted to be used in the foam industry in 2020 will be 30-40% greater 

than would be achieved by the same quantity of CFCs. The optimisation of hydrocarbon technologies 

over the years has also resulted in improvements in thermal performance through improved cell 

structure, thereby negating some of the earlier concerns about poorer thermal efficiency. 

Carbon Dioxide as a blowing agent

Although carbon dioxide (CO2) is generated as a by-product of the reaction between isocyanates and 

water in polyurethane chemistry (so called CO2 (water) technology), the main focus of this section is 

on the external addition of gaseous CO2 as a blowing agent. This is particularly a technology 

practiced in the Extruded Polystyrene sector, where the main low-GWP and cost-effective 

alternative has been CO2 injected into the extruder itself. Again, the main challenge throughout has 

been to understand why this solution could not be universal in its application. Reasons have 

included:

 Processing difficulties with CO2 and even CO2/HCO or CO2/HC blends

 The higher gaseous thermal conductivity leading to poorer thermal efficiency of the foam 

 Costs of conversion - including licensing constraints resulting from patents

 Loss of processing flexibility ruling out some board geometries completely

For these reasons considerable proportions of the extruded polystyrene (XPS) industry have 

remained using HCFCs and HFCs rather than CO2. This has been particularly the case in North 

America where the product requirements are for wide and thin boards to meet the residential 

sheathing market. By contrast, much of the European XPS market is targeted at requirements, such 

as floor insulation, where its moisture resistance is particularly valuable. In these applications, board 

geometries are less critical. 

Injected (super-critical) CO2 is also used for PU Spray Foam applications – most notably in Japan, 

where PU Spray Foam is widely used. The technology is proprietary to one company and this has 

arguably limited its adoption on a wider basis. There are also some short-comings in thermal 

performance against other technological solutions in the sector, especially in relation to the 

emerging unsaturated fluorocarbons (see next section). 

Latest Status of Unsaturated HFC/HCFC Developments 

In recent years, the search for low-GWP, high performance blowing agents without the limitations of 

hydrocarbons and CO2 has been continuing. For the first time, the emergence of unsaturated HCFCs 

and HFCs (often commercially referred to as HFOs) seems to be offering a level of performance 

which not only allows the replacement of blowing agents with high-GWPs such as HCFCs and 

saturated HFCs, but also has the potential to replace some elements of the hydrocarbon and CO2-

blown sectors, based primarily on improved thermal properties. This is particularly the case in the 

PU Appliance sector, where at least three Asian manufacturers have already adopted HFO 

technology alongside their non-Article 5 competitors. In practice, and for cost reasons, blends of 

HFOs with other blowing agents are likely to be favoured. Although the situation is becoming clearer 

with these technologies, there are still some uncertainties over the overall system cost and the 

global availability. Commercial availability has already been established for HFO-1234ze(E) (gaseous 
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blowing agent) and HFO-1233zd(E) (liquid blowing agent). Pilot scale production of HFO1336mzzm(Z) commenced in late 2014, with full commercialisation expected in 2016. However, for 

all of these options availability is likely to be targeted mostly in markets where the requirement for 

improved thermal efficiency is best identified. In addition, the demand to leap-frog high GWP HCFC 

alternatives in other sectors could further accelerate distribution in Article 5 regions. This is 

especially the case in the rapidly growing XPS sector where the emergence of gaseous unsaturated 

HFCs such as HFO-1234ze presents a significant opportunity to replace any remaining HCFCs, 

saturated HFCs and even CO2 in some instances. However, cost remains a key issue and blending 

with oxygenated hydrocarbons (e.g. dimethyl ether) may well be required to deliver a commercially 

viable alternative technology. 

Progress with other Low GWP Alternative Blowing Agents 

Other blowing agents are also emerging as potential replacements for HCFCs and HFCs. These 

include a group of oxygenated hydrocarbons (HCOs) which include methyl formate and methylal. 

These are generally seen as less flammable than the hydrocarbons themselves, although the 

significance of those differences can often depend on local product codes and the regulatory 

frameworks governing foam manufacture. Again, there is a growing tendency to see these used as 

components of tailored blends where they can contribute to overall performance criteria. 

In summary, Table 1 provides an overview of the blowing agent classes which have either been 

previously offered, or are currently being offered, alternatives to ozone depleting substances in the 

sectors being specifically considered in this report. The table has been simplified over that of 

previous years by the fact that the Arkema product previously described as AFA-1 has now been 

confirmed as HFO-1233zd(E), which aligns it with the existing Honeywell product. 

Sector CFCs HCFCs HFCs HCs HCOs HFOs CO2-based

ODS being replaced

PU Appliances CFC-11 HCFC-141b

HCFC-22

HFC-245fa

HFC-365mfc/227ea

cyclo-pentane

cyclo/iso-pentane

MethylΔ

Formate

HFO-1233zd(E)

HFO-1336mzzm(Z) CO2 (water)*Δ

PU Board CFC-11 HCFC-141b HFC-365mfc/227ea n-pentane

cyclo/iso pentane

HFO-1233zd(E)

HFO-1336mzzm(Z)

PU Panel CFC-11 HCFC-141b HFC-245fa

HFC-365mfc/227ea

n-pentane

/iso pentane

HFO-1233zd(E)

HFO-1336mzzm(Z) CO2 (water)*

PU Spray CFC-11 HCFC-141b HFC-245fa

HFC-365mfc/227ea

HFO-1233zd(E)

HFO-1336mzzm(Z)

CO2 (water)*

Super-critical 

CO2

PU In-situ/Block CFC-11 HCFC-141b HFC-245fa

HFC-365mfc/227ea

n-pentane

cyclo/iso pentane

HFO-1233zd(E)

HFO-1336mzzm(Z) CO2 (water)*

PU Integral Skin CFC-11 HCFC-141b

HCFC-22

HFC-245fa

HFC-134a

Methyl 

Formate

Methylal

CO2 (water)*

XPS Board CFC-12 HCFC-142b

HCFC-22

HFC-134a

HFC-152a DME HFO-1234ze(E) CO2CO2/ethanol

Phenolic CFC-11 HCFC-141b HFC-245fa

HFC-365mfc/227ea

n-pentane

cyclo/iso pentane

HFO-1233zd(E)

HFO-1336mzzm(Z)

*CO2(water) blown foams rely on the generation of CO2from reaction of isocyanate with water in the PU system itself

Δ Primarily in the commercial refrigeration sector (e.g. vending machines) 

Table 1: Range of blowing agents available by product type and market sector 

The next section of this report now reviews these selection trends sub-sector by sub-sector.
18 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

6. Review of blowing agent selection by foam sub-sector and region

Polyurethane Foams in the Refrigeration Sector

Commercially available alternatives to ODS 

Table 2 below gives an overview of the alternatives currently available for refrigeration applications: 

HCFC REPLACEMENT OPTIONS FOR APPLIANCES (DOMESTIC & COMMERCIAL), 

TRUCKS & REEFERS

SECTOR/OPTION PROS CONS COMMENTS

Domestic refrigerators/freezers

Cyclopentane & cyclo/iso blends

Low GWP Highly flammable

High incremental capital costs but 

most enterprises in sub-sector are 

large

Low operating costs Global industry standard 

Good foam properties

Saturated HFCs (HFC-245fa)

Non-flammable High GWP Low incremental capital costs

High operating costs Improved insulation (cf. HC)

Good foam properties Well proven technology

Commercial refrigerators/freezers plus vending equipment

Cyclopentane & cyclo/iso blends

Low GWP Highly flammable High incremental capital cost, 

may be uneconomic for SMEs

Low operating costs Well proven technology

Good foam properties

HFC-245fa, HFC-365mfc/227ea

Non-flammable High GWP Low incremental capital cost

Good foam properties High operating costs Improved insulation (cf. HC)

CO2 (water)

Low GWP

Moderate foam 

properties – high thermal 

conductivity & high foam 

density

Low incremental capital cost

Non-flammable High operating costs 

Improved formulations (second 

generation) claim no need for 

density increase vs HFC co-blown

Methyl Formate

Low GWP

Moderate foam 

properties -high thermal 

conductivity & high foam 

densityModerate incremental capital cost 

(corrosion protection 

recommended)

Flammable although 

blends with polyols may 

not be flammable

High operating costs 

Refrigerated trucks & reefers

Cyclopentane & cyclo/iso blends

Low GWP Highly flammable High incremental capital cost, may 

be uneconomic for SMEs

Low operating costs

Good foam properties

HFC-245fa, HFC-365mfc /227ea

Non-flammable High GWP Low incremental capital cost

Good foam properties High operating costs Improved insulation (cf. HC)

CO2 (water)

Low GWP

Moderate foam 

properties -high thermal 

conductivity & high foam 

densityLow incremental capital cost

Non-flammable High operating costs Not used in reefers

Table 2: Assessment of selection criteria for ODS alternatives in the Refrigeration Sector 

The assessment of these alternatives against the criteria of commercial availability, technical proof 

of performance, environmental soundness (encompassing efficacy, health, safety and environmental 

characteristics), cost effectiveness (capital and operating) and processing versatility in challenging 

ambient conditions is, in itself, a challenging objective. Typically, performance against such criteria 

can only be judged fully on a case-by-case basis and assessments made at a higher level will only be 
19 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

indicative. With this in mind, the following table seeks to give such an indicative assessment based 

on a nominal ranking of seven categories from ‘+++’ (the best) to ‘---‘ (the worst): 

Table 3: Indicative assessment of criteria for current ODS alternatives in the Refrigeration Sector 

As has been noted in previous reports, the mix of performance properties (technical, economic and 

environmental) does not lead unambiguously to one single selection. Indeed, the proliferation of 

blends across the whole of the foam sector and nowhere more so than the appliance sector is an 

indication of the reality that there is no single best solution. Often a key factor is the size of the 

manufacturing plant, since the economies of scale have a considerable bearing on the relative 

importance of capital and operational costs. Cost also is a major factor in the consideration of the 

major emerging technologies.

Emerging Alternatives

As noted in previous reports, the major emerging technologies in the appliance sector are based 

mostly around liquid unsaturated HCFCs/HFCs. These are all fairly similar in their properties and all 

seem to suggest a stepwise improvement in thermal performance over other low-GWP alternatives. 

HFO-1233zd (E) successfully started to be used at a major global appliance player in June 2014. Table

4 provides an overview of the ‘pros’ and ‘cons’ of these technologies.

HCFC REPLACEMENT OPTIONS FOR APPLIANCES (DOMESTIC & COMMERCIAL), 

TRUCKS & REEFERS

SECTOR/OPTION PROS CONS COMMENTS

Domestic refrigerators/freezers

Unsaturated HFC/HCFCs 

(HFOs) 

Low GWP High operating costs

Successfully trialled in 2012/13 

and commercial adoption now 

underway

Non-flammable

Improved energy efficiency 

performance: typically better than 

saturated HFCs

Low incremental capital cost

Commercial refrigerators/freezers plus vending equipment

Liquid Unsaturated HFC/HCFCs 

(HFOs) 

Low GWP High operating costs Following domestic appliance 

trends with blends being adopted

Non-flammable

Improved energy efficiency 

performance: typically better than 

saturated HFCs

Low incremental capital cost

Refrigerated trucks & reefers

Liquid Unsaturated HFC/HCFCs 

(HFOs) 

Low GWP High operating costs Although HFOs commercialised, 

limited case experience available

Non-flammable

Improved energy efficiency 

performance: typically better than 

saturated HFCs

Low incremental capital cost

Table 4: Emerging alternatives to ODS in the Refrigeration Sector
20 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

The range of unsaturated HCFCs/HFCs has been reduced from the selection provided in the Decision 

XXIV/7 Report. The disclosure of the molecule behind Arkema’s code name AFA-L1 occurred in 

September 2013, and revealed it as the same molecule being developed and commercialised by 

Honeywell. However, Table 5 provides an analysis of these new molecules against the criteria 

considered for the commercially available alternatives based on limited experience in appliance 

sector trials. 

HFO-1234ze(E) HFO-1336mzzm(Z) HFO-1233zd(E)

Gaseous liquid liquid

Proof of performance + ++ ++

Flammability ++ +++ +++

Other Health & Safety + + +

Global Warming +++ +++ +++

Other Environmental + + +

Cost Effectiveness (C) ++ ++ ++

Cost Effectiveness (O) -- -- --

Process Versatility + + +

Table 5: Indicative assessment of criteria for emerging ODS alternatives in the Refrigeration Sector

As noted above, the commercialisation time-line and global availability of the various unsaturated 

HCFCs/HFCs will have a considerable bearing on their widespread adoption under the HCFC Phaseout Management Plans currently being enacted. Two of the three potential manufacturers are 

committing to timelines of 2015 or better, but the supply/demand curves for these alternatives are 

still not fully understood. As noted earlier, one major manufacturer has started up global scale 

plants for both gaseous and liquid HFOs in the last two years. 

One factor in the adoption of these new technologies is the potential use of blends of unsaturated 

HFCs/HCFCs with hydrocarbons to achieve intermediate thermal performance benefits at affordable 

cost. If the compromises made are too great, then the benefits will be too marginal to justify 

transition from existing hydrocarbon solutions where they are already in place, and to prefer 

unsaturated HCFC/HFC solutions over hydrocarbon where they are not. However, with the cost of 

these new compounds not completely established at this point, it is not clear whether solutions 

maximising the thermal performance benefits will be affordable. 

For those still using HCFC-141b, one strategy being considered in the case of some manufacturers is 

to make an intermediate transition to a high-GWP (lower investment) technology option such as 

saturated HFCs on the written understanding that a further transition to a low-GWP option will 

follow within a specified period. The choice would be left open until such time as optimum 

technology approaches have been established. 

For transitions directly from HCFC-141b to hydrocarbons, there are potential strategies to reduce 

the investment costs for smaller enterprises. These include the potential for using pre-blended mixes 

containing cyclo-pentane. However, this approach is not expected to impact the domestic appliance 

sector too greatly, since economies of scale would generally support a more comprehensive 

conversion strategy. However, in the case of some manufacturers of commercial appliances (e.g. 

vending machines), there may be more relevance. 

Non-Article 5 Parties

In Europe and Japan, the dominant blowing agent choices have been hydrocarbon blends, even at 

the point of phase-out from CFC use in the early/mid 1990s. Cyclo-pentane was a favoured 

component of blends because of its contributions to improved thermal performance and its higher 
21 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

boiling/flash point. However, its lack of blowing efficiency in pure form and the impact of this on 

processing and cost often led to the blending with components such as iso-pentane or n-pentane. 

Therefore, cyclo-iso blends have been a common feature of the domestic appliance industry and still 

remain so. 

In North America, the technology choice was driven in a different direction – partly by the overall 

size and design of refrigerators and partly because of safety and insurance concerns from a 

manufacturing perspective. Transitions from CFCs moved to HCFCs and then, primarily, to HFC245fa. There has also been some use of HFC-134a in the sector and, more recently, the removal of 

patent restrictions has allowed for the introduction of HFC-365mfc/227ea blends. Therefore, the 

domestic appliance industry in this region remains largely dependent on high GWP HFCs. 

For commercial appliances and more complex insulated containers, the blowing agent choices have 

been more varied, with greater reliance on lower flammability options. In some instances (e.g. in 

vending machines), this has encouraged the use of oxygenated hydrocarbons such as methyl 

formate and, to a lesser degree methylal. In addition, there has been widespread reliance on HCFCs 

and, more latterly high GWP HFCs. 

Although there are no obvious pressures to change technologies in any of the regions referenced 

above, the emergence of unsaturated HFCs and HCFCs has generated particular interest in all 

regions. The main reason is that these molecules offer improved thermal insulating properties in an 

application where maximising thermal performance and minimising insulation thickness are 

desirable outcomes. Whether additional market pressures in North America relating to the 

continued use of high-GWP HFCs will add to the pressure to adopt blends containing the 

unsaturated molecules is not yet clear. 

Article 5 Parties

Similar trends exist for in the highly populated Article 5 Parties where multi-national companies are 

often seeking to adopt global technology strategies. In some cases, the transition from HCFCs to 

alternatives has not yet occurred and there are opportunities to avoid high-GWP HFCs. However, the 

Multilateral Fund process does not direct influence over these technology choices, since funding is 

usually not provided. Instead it falls on individual Parties to negotiate a phase-out strategy with their 

industries. This matter is covered further in Chapter 4. Interest in unsaturated HFCs and HCFCs is 

expected to mirror the decisions made in non-Article 5 regions. 

For those transitions covered under the Multilateral Fund, it has been possible to direct virtually all 

HCFC phase-out activities towards low-GWP alternatives including pre-blended hydrocarbon, methyl 

formate and methylal. Transitions will not be complete before 2015, at which point the full degree of 

coverage of these technologies will be more self-evident.

Polyurethane Boardstock 

This is one of the largest markets for rigid polyurethane foams in non-Article 5 Parties, but has only 

recently started to grow significantly in Article 5 Parties as requirements for building energy 

efficiency have increased. The historical analysis therefore focuses primarily on the non-Article 5 

experiences. 

Commercially available alternatives to ODS 

Table 6 below gives an overview of the alternatives currently available for boardstock applications
22 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Table 6: Assessment of selection criteria for ODS alternatives in the Boardstock Sector

In general, saturated HFCs have shown little uptake in most PU Boardstock markets because the 

hydrocarbon-based products have been shown to be fit-for-purpose at a more competitive cost. 

Since new capacity in the industry can accommodate hydrocarbon process safety issues at the 

design stage, the high incremental capital costs associated with later transitions can be mitigated to 

some extent. 

As building energy standards increase, there could be increasing pressure for better thermal 

efficiency, especially where space is limited and product thickness is constrained. There has 

therefore been some interest in possible blends of hydrocarbons with saturated HFCs. Indeed, it is 

suspected that some manufacturers may have adopted this strategy commercially, although it is 

difficult to track because no further plant modifications would normally be necessary. Such trends 

may also be short-lived, since there is increasing market pressure (e.g. through LEED and other 

environmental building schemes) to avoid the use of saturated HFCs.

According to the chosen criteria, the relative performance of alternative technology solutions in this 

sector can be summarised as follows: 

c-pentane n-pentane i-pentane HFC-245fa HFC365mfc/227ea

Proof of performance +++ +++ +++ ++ ++

Flammability --- --- --- ++ +(+)

Other Health & Safety 0 0 0 + +

Global Warming +++ +++ +++ -- ---

Other Environmental - - - 0 0

Cost Effectiveness (C) -- -- -- ++ ++

Cost Effectiveness (O) ++ +++ +++ -- --

Process Versatility ++ ++ ++ ++ +

Table 7: Indicative assessment of criteria for current ODS alternatives in the Boardstock Sector 

The slight environmental concerns reflected for hydrocarbon options relate to some emerging 

concerns about local VOC regulations. In some regions there are exemptions for thermal insulation 

manufacturing plants, but this approach is not universal.

 

Emerging Alternatives

The market pressure on saturated HFCs outlined in the previous section opens up the possibility for 

hydrocarbon blends with unsaturated fluorocarbons (both HCFCs and HFCs). The uncertainty of cost 

makes this option even less clear cut for PU Boardstock than it is for domestic appliances. 

Nonetheless, there continues to be sufficient interest in the option to justify its inclusion in this 

section as an emerging technology – albeit as a blend with hydrocarbons. 
23 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

HCFC REPLACEMENT OPTIONS FOR PU FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Boardstock – continuously produced

Liquid Unsaturated HFC/HCFCs 

(HFOs) Low GWP High operating costs With blowing agent costs a high % of overall system costs, blends are essential

Non-flammable Successfully trialled, particularly with 

blends. Re-standardisation underway. 

Low incremental capital cost

Table 8: Emerging alternatives to ODS in the Boardstock Sector

The overall assessment of the criteria for unsaturated HCFCs/HFCs is very similar to that shown for 

PU appliances.

HFO-1234ze(E) HFO-1336mzzm(Z) HFO-1233zd(E)

Gaseous Liquid Liquid

Proof of performance + ++ ++

Flammability ++ +++ +++

Other Health & Safety + + +

Global Warming +++ +++ +++

Other Environmental + + +

Cost Effectiveness (C) ++ ++ ++

Cost Effectiveness (O) -- -- --

Process Versatility + + +

Table 9: Indicative assessment of criteria for emerging ODS alternatives in the Boardstock Sector

The only potential difference is that the use of a gaseous option being used in the PU Appliances 

sector is less likely than for PU Boardstock. Nevertheless, it has been retained for completeness.

In practice, the quantity of PU Boardstock foam still using HCFCs is very limited and this fact alone 

testifies to the lack of barriers to appropriate transition. As noted earlier, much of the new capacity 

in the sector has been installed since the ozone issue emerged and the necessary requirements for 

hydrocarbon have typically been designed in.

The only likely transition pressure now emerging relates to the on-going goal of improved thermal 

efficiency. The major barrier to the adoption of blends of saturated HFCs with hydrocarbons is 

market pressure, while the potential barrier to the wider use of unsaturated HCFCs/HFCs is one of 

cost and, in the short term, availability.

Non-Article 5 Parties

In virtually all non-Article 5 regions, hydrocarbons (typically a mixture of cyclo-pentane and isopentane) have been the dominant choice of blowing agent in the replacement of ozone depleting 

substances. Accordingly, this is reflected in the Business-As-Usual scenario used for this report. 

There may be some future interest in the evaluation of unsaturated HCFCs/HFCs, but the cost is 

likely to be prohibitive in this cost sensitive application unless space saving is at a premium. 

Article 5 Parties

There is no significant manufacture of boardstock in Article 5 regions with the possible exception of 

China. However, where new capacity is installed, it is highly likely that the blowing agent of choice 

will once again be hydrocarbons. 
24 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Polyurethane Panels 

In the context of this analysis, the primary panels being referred to are steel-faced and either 

continuously or discontinuously produced. The market for such panels has developed very 

differently in various regions of the world, with the early adoption being mostly in Europe. However, 

the prefabricated approach to building that these panels allow is becoming increasingly widespread 

globally and manufacturing capacity has continued to grow to meet the need. 

Commercially available alternatives to ODS 

Table 10 provides an overview of the commercially available alternatives in both the continuous and 

discontinuous panel sectors: 

HCFC REPLACEMENT OPTIONS FOR PU FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Steel-faced panels – continuously produced

Cyclopentane & n-Pentane

Low GWP Highly flammable

High incremental capital costs 

but most enterprises in subsector are large 

Low operating costs Industry standard

Good foam properties

HFC-245fa, HFC-365mfc/227ea

Non-flammable High GWP Low incremental capital cost

Good foam properties High operating costs

Improved insulation (cf. HC)

Steel-faced panels – discontinuously produced

Cyclopentane & n-Pentane

Low GWP Highly flammable High incremental capital cost, 

may be uneconomic for SMEs 

Low operating costs

Good foam properties

HFC-245fa, HFC-365mfc/227ea, 

HFC-134a

Non-flammable High GWP Low incremental capital cost

Good foam properties High operating costs Improved insulation (cf. HC)

CO2 (water)

Low GWP

Moderate foam properties 

-high thermal 

conductivityLow incremental capital cost

Non-flammable

Methyl Formate/Methylal

Low GWP

Moderate foam properties 

- high thermal 

conductivityModerate incremental capital 

cost (corrosion protection 

recommended)

Flammable although 

blends with polyols may 

not be flammable

Table 10: Assessment of selection criteria for ODS alternatives in the PU Panel Sector

The pressure for improved thermal performance in the architectural (cladding) panel is less 

pronounced than it is for other building insulation types because of the structural requirements 

which are associated with that application. However, the same cannot be said for refrigerated 

transport where additional benefits in thermal performance can improve the load-carrying capacity 

of a vehicle. Therefore, there is on-going interest in saturated HFCs as legitimate alternatives, or at 

least components of blends for that application. 

In the discontinuous sector, there are other potential technologies based around CO2 (water) and 

HCOs such as methyl formate or methylal. These reduce the perceived risks associated with the use 

of hydrocarbons on discontinuous plants but do result in some compromises in foam properties 

including higher density and potentially poorer thermal performance. Nonetheless, they do offer 
25 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

low-GWP solutions in markets, which may not be too sensitive to thermal performance issues. These 

are all important considerations in the Article 5 context where the need to phase-out HCFCs requires 

the widest range of alternatives, especially for small and mixed use discontinuous panel facilities. 

The strengths and weaknesses of these alternatives are once again shown in the Table 11 – this time 

relating to the panel sector. 

c-pentane

i-pentane 

n-pentane

HFC-245fa HFC365mfc/227ea CO2(water) Methyl 

Formate

Proof of performance + ++ ++ ++ ++ +

Flammability --- --- ++ +(+) +++ --

Other Health & Safety 0 0 + + - 0

Global Warming +++ +++ -- --- ++ ++

Other Environmental - - 0 0 ++ -

Cost Effectiveness (C) -- --- ++ ++ ++ 0

Cost Effectiveness (O) ++ +++ -- -- + +

Process Versatility ++ ++ + ++ + +

Table 11: Indicative assessment of criteria for emerging ODS alternatives in the PU Panel Sector

Emerging Alternatives

Again, the major emerging alternatives are unsaturated HCFCs/HFCs. In view of the relative 

abundance of commercially available alternatives, these blowing agents are likely to be focused on 

niche markets in the panel sector. 

HCFC REPLACEMENT OPTIONS FOR PU FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Steel-faced panels – continuously produced

Liquid Unsaturated HFC/HCFCs 

(HFOs)

Low GWP High operating costs

Cost sensitivity less significant, 

but thermal performance 

improvement also less critical

Non-flammable Trials in progress

Low incremental capital cost

Steel-faced panels – discontinuously produced

Liquid Unsaturated HFC/HCFCs 

(HFOs)

Low GWP High operating costs First expected commercialization 

in 2013

Non-flammable Trials in progress

Low incremental capital cost

Table 12: Emerging alternatives to ODS in the PU Panel Sector

In principle, unsaturated HCFCs/HFCs offer opportunities for improving thermal performance while 

retaining a low-GWP blowing agent. For reasons stated in respect of other foam sectors, the cost of 

these blowing agents is still uncertain and could prevent reliance on them in isolation. That said, the 

added value of a panel is certainly greater than that of boardstock, so the ability to adsorb cost could 

be greater in this sector. Nevertheless, the most likely approach will be the adoption of blends with 

hydrocarbons provided that an incremental improvement in thermal performance can be achieved. 

This will be particularly important for the thermally sensitive applications such as refrigerated 

transport. The proof of performance is at a lower level in this sector than elsewhere and this is 

reflected in Table 13:
26 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

HFO-1234ze(E) HFO-1336mzzm(Z) HFO-1233zd(E)

Gaseous liquid Liquid

Proof of performance 0 + +

Flammability ++ +++ +++

Other Health & Safety + + +

Global Warming +++ +++ +++

Other Environmental + + +

Cost Effectiveness (C) ++ ++ ++

Cost Effectiveness (O) -- -- --

Process Versatility + + +

Table 13: Indicative assessment of criteria for emerging ODS alternatives in the PU Panel Sector

The major barriers to the substitution of alternatives in the panel sector are not primarily related to 

the technologies available but to the wide range of enterprises involved (both in size and location) 

and the broad spectrum of applications served. Versatility is a key necessity for any technology in 

the discontinuous sector, but no single solution has emerged as being as versatile as the ozone 

depleting substances replaced. This may act as a deterrent to early phase-out of the remaining HCFC 

use in Article 5 enterprises where local requirements need to be matched. 

Non-Article 5 Parties

For the continuous panel sector, hydrocarbons have also been the blowing agent of choice except 

where fire performance requirements have dictated otherwise. In these limited instances, high-GWP 

HFCs have been adopted. Increasingly the industry has found ways of optimising formulations to 

improve fire performance while still using hydrocarbons and the use of saturated HFCs has steadily 

decreased over the last five years. This is reflected in the Business-as-Usual scenario used for this 

report. 

For discontinuous panel manufacture, there has been greater reliance on high-GWP HFCs as 

replacements for HCFCs in order to overcome flammability concerns during processing. 

Nevertheless, similar trends to those with continuous panels are now being observed as 

manufacturers become more skilled and experienced in managing hydrocarbons in production 

situations.

Article 5 Parties

There is a greater preponderance of discontinuous production in Article 5 regions because of the 

lack of concentrated demand to support continuous production facilities. This has ensured 

continued use of HCFCs in many small discontinuous panel manufacturing uses. Although 

oxygenated hydrocarbons (HCOs) such as methyl formate and methylal are also being considered for 

this sector, the uptake at present is still relatively low. 

Polyurethane Spray 

Polyurethane spray foam has been used for many years as an efficient means of insulating structures 

which would be difficult to insulate in other ways, because of shape or location. An example would 

be that of an insulated road tanker. Another would be the insulation of large flat roofs, which may 

not be as flat as might be presumed! More recently, however, polyurethane spray foams have 

emerged as a vital component of renovation strategies for existing buildings. Again, the efficiency 

and versatility of application, as well as the relative durability and thermal efficiency are all 

characteristics, which have contributed to the rapid growth of PU spray foam in both developed and 

developing regions.
27 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Commercially available alternatives to ODS 

The commercially available technologies have been largely referenced already in the narrative, but 

can be summarised as follows: 

HCFC REPLACEMENT OPTIONS FOR PU FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Spray foam

Cyclopentane & n-Pentane Low GWP Highly flammable Unsafe to use in this application

HFC-245fa, HFC-365mfc/227ea

Non-flammable High GWP Industry standard

Good foam properties

High operating costs but 

improved by using mixed 

HFC/ CO2 (water)

CO2 (water) Low GWP

Moderate foam properties 

-high thermal conductivity 

& high densityExtra thickness leading to a cost 

penalty

Non-flammable

Methyl Formate Low GWP

Flammable although 

blends with polyols may 

not be flammable

Safety concerns when used for 

this application

Table 14: Assessment of selection criteria for ODS alternatives in the PU Spray Foam Sector

It is important to note that the impacts of the saturated HFCs have been reduced by co-blowing with major 

drivers has been to reduce cost. As will be seen later in this sub-section this may be an important approach 

for the future.

Methyl formate has also been used for some PU spray work. The potential of supplying the system to site 

as blended polyol is believed to contribute to the management of risk, but it is still unclear whether the 

hazards seen with hydrocarbons in confined spaces have been avoided using methyl formate. Work 

continues in this area, although some systems are already being used commercially. The performance of 

these ODS alternatives against the criteria for this report can be summarised as shown in Table 15: 

HFC-245fa HFC365mfc/227ea Super-critical CO2 CO2(water) Methyl 

Formate

Proof of performance +++ +++ ++ ++ +

Flammability ++ +(+) ++ +++ --

Other Health & Safety + + + - 0

Global Warming -- --- ++ ++ ++

Other Environmental 0 0 + ++ -

Cost Effectiveness (C) ++ ++ 0 ++ 0

Cost Effectiveness (O) -- -- + ++ ++

Process Versatility ++ ++ + + +

Table 15: Indicative assessment of criteria for emerging ODS alternatives in the PU Spray Sector

Emerging Alternatives

Alongside the appliance sector, the PU spray foam sector is attracting the most interest for potential 

adoption of the unsaturated HCFCs/HFCs. The rapid growth rate for the sector overall, the absence 

of serious low-GWP contenders and the fact that relatively high emission rates make the climate 

impact more immediate all align to encourage the manufacturers to focus on this application. 
28 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

HCFC REPLACEMENT OPTIONS FOR PU FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Spray foam

Liquid Unsaturated HFC/HCFCs 

(HFOs)

Low GWP

High operating costs but 

improved by using mixed 

HFC/ CO2 (water)

First expected commercialization 

from 2013

Non-flammable Trials in progress

Low incremental capital cost

Table 16: Emerging alternatives to ODS in the PU Spray Foam Sector

The cost of the alternatives remains the key question but this consideration is slightly diffused by the 

fact that the CO2 (water) technology developed around HFC-245fa and HC-365mfc/227ea looks 

transferable to the unsaturated blowing agents as well. Manufacturers are in the process of field 

trials and the development of fairly sophisticated life cycle assessments to ensure that they have 

assessed the environmental impacts correctly. The co-blowing solution does not detract significantly 

from the overall thermal performance of the foam and the introduction of a low-GWP solution of 

this type would clear the way for widespread use of PU spray foam in a wide variety of 

refurbishment applications over the next 30-50 years as global attention focuses increasingly on 

building energy efficiency in existing stock. However, there are emerging concerns about the 

potential stability of the gaseous unsaturated blowing agents in low-pressure, pre-blended 

formulations. This is the subject of intense further development work, but no immediate solution 

has so far been forthcoming. The following table has been updated accordingly. 

HFO-1234ze(E) HFO-1336mzzm(Z) HFO-1233zd(E)

Gaseous liquid Liquid

Proof of performance 0 + +

Flammability ++ +++ +++

Other Health & Safety + + +

Global Warming +++ +++ +++

Other Environmental + + +

Cost Effectiveness (C) ++ ++ ++

Cost Effectiveness (O) -- -- --

Process Versatility + + +

Table 17: Indicative assessment of criteria for emerging ODS alternatives in the PU Spray Sector

Since the future of the sector rests largely on the emerging technologies, the main barriers relate to 

the stability, economics and availability of the unsaturated blowing agents. Much of the PU spray 

foam activity in China remains reliant on HCFC-141b and there is reluctance to make a transition to a 

sub-optimal solution when an emerging technology could out-perform it within 5 years. Various 

strategies are being considered including a two-step option via saturated HFCs. However, there is a 

need to gain commitment to the second conversion at the outset. 

Non-Article 5 Parties

This remains one of the most challenging areas from a technical viewpoint, because of the 

processing risks associated with using hydrocarbons in field applications. As a result, HCFCs were 

replaced en masse by high-GWP blowing agents such as HFC-245fa (particularly in North America) 

and HFC-365mfc/227ea (particularly in Europe). Although unsaturated HCFCs/HFCs are seen as a 

future replacement, emerging concerns about the stability of the gaseous blowing agent (HFO 

1234ze(E)) in certain low-pressure pre-blended formulations are placing some doubt on the ability of 
29 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

these technologies to reach their full potential. Accordingly, the Business-As-Usual scenario remains 

focused on high-GWP solutions for these low-pressure applications for the moment.

Article 5 Parties

For similar reasons to those expressed for non-Article 5 regions, PU Spray foam in Article 5 regions 

remains highly reliant on HCFCs. If the concerns about unsaturated HCFCs/HFCs continue for any 

significant period of time, contractors and systems houses may need to investigate the possibility of 

moving to a high-GWP interim solution in order to exit from HCFC-141b use in a timely manner. 

Polyurethane In-situ/Block 

One of the enduring advantages of polyurethane chemistry in general, and polyurethane foams in 

particular, is their ability to meet a broad range of applications. Since these applications can be 

diverse, ranging from cavity filling (e.g. buoyancy on leisure boats) to the fabrication of complex 

shapes required for pipe and flange insulation, the in-situ and block processes provide a resource to 

meet these needs. Self-evidently, these applications are also difficult to track in any organised way 

since they vary so much. Nevertheless, it is possible to track the manufacturing facilities that provide 

these products and services.

Commercially available alternatives to ODS 

The commercially available alternatives to HCFCs in the in-situ and block sectors are summarised in 

Table 18:

HCFC REPLACEMENT OPTIONS FOR PU FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Insulated pipes (pipe-in-pipe for district central heating systems)and other in-situ systems

Cyclopentane 

Low GWP Highly flammable High incremental capital cost

Low operating costs Industry standard

Good foam properties

HFC-245fa, HFC-365mfc/277ea Non-flammable High GWP

Good foam properties High operating costs 

CO2 (water)

Low GWP

Moderate foam properties 

-high thermal 

conductivityNon flammable

Block foams for various applications including panels, pipe insulation section, etc

Cyclopentane & n-Pentane 

Low GWP Highly flammable High conversion costs, may be 

uneconomic for SMEs

Low operating costs Well proven technology

Good foam properties

HFC-245fa, HFC-365mfc/277ea

Non-flammable High GWP Low conversion costs

Good foam properties

High operating costs but 

improved by using mixed 

HFC/ CO2 (water)

CO2 (water)

Low GWP

Moderate foam 

properties -high thermal 

conductivity & poor 

ageingExtra thickness leading to a cost 

penalty

Non flammable

Table 18: Assessment of selection criteria for ODS alternatives in the PU In-situ/Block Foam Sector

As with other thermal insulation sectors, saturated HFCs are used in block foams with a CO2 (water) 

co-blowing agent to limit climate impact and also to optimise the cost/performance relationship. It 

has generally been found that levels of saturated HFC can be lowered in these formulations to 
30 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

around 50-60% of the blowing agent mix without having a detrimental effect on thermal 

performance. The blowing agent criteria for block and in-situ foams are shown below. In some 

instances, more than one rating is providing reflecting the fact that there is a disparate set of 

processes represented in this category. 

c-pentane n-pentane HFC-245fa HFC365mfc/227ea CO2(water)

Proof of performance +/++ +/++ ++ ++ ++

Flammability --- --- ++ +(+) +++

Other Health & Safety 0 0 + + -

Global Warming +++ +++ -- --- ++

Other Environmental - - 0 0 ++

Cost Effectiveness (C) -- --- ++ ++ ++

Cost Effectiveness (O) ++ +++ -- -- +

Process Versatility ++ ++ ++ ++/+++ +/++

Table 19: Indicative assessment of criteria for emerging alternatives in the PU In-situ/Block Sector

 

Emerging Alternatives

In this instance, the Foams TOC has chosen to categorise methyl formate and methylal in the 

emerging alternative category. This reflects the fact that some of the applications across the sector 

have yet to be trialled using this HCO blowing agent. There are expected to be some limitations 

based on densities achievable and risks of corrosion with some equipment, but the availability of a 

relatively low cost, low-GWP solution with lower flammability than the pentanes may still prove of 

relevance for the sector going forward.

HCFC REPLACEMENT OPTIONS FOR PU FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Block foams for various applications including panels, pipe insulation section, etc

HCO (Methyl Formate/Methylal) Low GWP Higher density required Density increase necessary 

through role of MF as a solvent 

Liquid Unsaturated HFC/HCFCs 

(HFOs

Low GWP High operating costs Trials in progress

Non-flammable 

Table 20: Emerging alternatives to ODS in the PU In-situ/Block Foam Sector

The option of liquid unsaturated HCFCs/HFCs in this sector is legitimate, but there is some concern 

that price and geographic availability may be significant limiting factors. Again, co-blowing with CO2 

(water) may prove helpful for cost reasons, but uptake is expected to be more limited than in other 

sectors of the foam industry. The following table shows an assessment against the report criteria: 

Methyl Formate HFO-1336mzzm(Z) HFO-1233zd(E)

Liquid Liquid

Proof of performance 0/+ ++ ++

Flammability -- +++ +++

Other Health & Safety + + +

Global Warming +++ +++ +++

Other Environmental + + +

Cost Effectiveness (C) ++ ++ ++

Cost Effectiveness (O) -- -- --

Process Versatility + ++ ++

Table 21: Indicative assessment of criteria for emerging alternatives in the PU In-situ/Block Sector
31 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

One of the major barriers to transition in this sector is the size and location of the enterprises 

involved. The provision of sophisticated low-GWP alternatives does not extend easily to these more 

diffuse networks and the effectiveness of transitions relies massively on the competence and 

commitment of the systems houses supplying the small and micro-enterprises. Efforts are needed to 

raise the profile of these operations with blowing agent technology providers and their supply 

networks.

Non-Article 5 Parties

These products can be made by a variety of processes, including continuous, semi-continuous and 

discontinuous options. Although there is some sensitivity to the use of hydrocarbons in some 

discontinuous facilities (see comments on discontinuous panels), the majority of products in this 

sector have been able to adopt hydrocarbon technologies successfully. There are possibilities that 

methyl formate or methylal might be able to replace saturated HFCs in some of the remaining 

discontinuous processes, but this will ultimately depend on local regulations and practices. 

Accordingly, little change is predicted in this sector within the next 5-10 years within the BusinessAs-Usual scenario.

Article 5 Parties

Similar concerns exist for discontinuous processes in Article 5 regions. As is the case in the panel 

sector, these are more prevalent in Article 5 regions because of lack of economies of scale. There are 

also differences in product demand with thermo-ware being a particular requirement in Southern 

Asia and elsewhere. For these reasons HCFCs continue to remain the blowing agent of choice, 

although uptake of methyl formate and/or methylal is predicted within a number of HPMPs. The 

magnitude of this uptake is varied in the Mitigation Scenarios selected for foams, but the Businessas-Usual scenario reflects a fairly conservative estimate of market penetration, with the remainder 

going to high-GWP HFCs. 

Polyurethane Integral Skin 

Integral skin foams are the one group of foams, which are not primarily used for thermal insulation 

purposes. They sub-divide into two types – ‘rigid integral skin’ (typically items such as wood 

replacement) and ‘flexible integral skin’ (typically covering items such as shoe soles and some 

packaging foams). As the name suggests, the primary feature of integral skin products is their ability 

to encapsulate a relatively low density core (for weight saving purposes) with an integrated skin 

which is made from the same material and in the same process. As a polymer, polyurethane is 

particularly versatile in forming a resilient skin when moulded and this provides a level of utility 

which is rarely seen in other product types. 

Commercially available alternatives to ODS 

Table 22 provides a summary of commercially available alternatives in the PU Integral Skin sector

HCFC REPLACEMENT OPTIONS FOR INTEGRAL SKIN PU FOAMS FOR TRANSPORT & FURNITURE 

APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Integral skin foams

CO2 (water) 

Low GWP Poor skin quality Suitable skin may require inmould-coating – added expense

Low conversion costs Well proven in application if skin 

acceptable

n-Pentane

Low GWP Highly flammable High conversion costs, may be 

uneconomic for SMEs

Low operating costs Low operating costs
32 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Good skin quality Well proven in application

Shoe-soles

CO2 (water) 

Low GWP Well proven in application with 

polyester polyol technology

Low conversion costs

Skin quality suitable for 

sports shoe mid-soles

HFC-134a or HFC-245fa Used to give required 

skin in town shoes High GWP/Cost

Table 22: Assessment of selection criteria for ODS alternatives in the PU Integral Skin Sector

The specific ranking of these blowing agent options is shown in Table 23 below. 

 n-pentane HFC-134a HFC-245fa CO2(water)

Proof of performance ++ ++ + ++

Flammability --- +++ ++ +++

Other Health & Safety 0 + + -

Global Warming +++ --- --- ++

Other Environmental - 0 0 ++

Cost Effectiveness (C) --- ++ ++ ++

Cost Effectiveness (O) +++ -- -- +

Process Versatility ++ ++ ++ 0

Table 23: Indicative assessment of criteria for emerging alternatives in the PU Integral Skin Sector

Emerging Alternatives

The area of most interest with respect to emerging technologies is the potential use of oxygenated 

hydrocarbons (HCOs). Both methyl formate and methylal are being considered for these applications 

and the early indications are that they could be significant future alternatives in the sector. Although 

both flammable, there is the potential that systems houses may be able to formulate blended 

systems in such a way as to avoid flammability issues in the workplace. One area of concern for 

methyl formate is the potential corrosion of moulds, but at the levels of addition and being a fairly 

emissive application, this may not be a problem in practice. The other issue relating to both HCOs 

the high solvency power of the blowing agents which could lead to some softening of the skins. 

Table 24 summarises the issues. 

It is noteworthy to mention that unsaturated HFCs/HCFCs are not seen as a realistic emerging 

technology in this sector because of the cost implications and the lack of any significant performance 

enhancement. 

HCFC REPLACEMENT OPTIONS FOR INTEGRAL SKIN PU FOAMS FOR TRANSPORT & FURNITURE 

APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Integral skin foams

Methyl formate

Low GWP

Flammable although 

blends with polyols may 

not be flammable

Moderate conversion costs 

Good skin quality Moderate operating 

costs

Newly proven in application 

Methylal

Low GWP

Flammable although 

blends with polyols may 

not be flammable

High conversion costs, may be 

uneconomic for SMEs

Good skin quality Moderate operating 

costs

Newly proven in application
33 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Shoe-soles

Methyl formate

Low GWP

Flammable although 

blends with polyols may 

not be flammable

Moderate conversion costs 

Good skin quality Moderate operating 

costs

Newly proven in application 

Methylal

Low GWP

Flammable although 

blends with polyols may 

not be flammable

High conversion costs, may be 

uneconomic for SMEs

Good skin quality Moderate operating 

costs

Newly proven in application

Table 24: Emerging alternatives to ODS in the PU Integral Skin Sector

Again, the specific performance ranking of the blowing agents is shown in the table below: 

Methylal Methyl Formate

Proof of performance + ++

Flammability -- --

Other Health & Safety 0 0

Global Warming ++ ++

Other Environmental - -

Cost Effectiveness (C) + 0

Cost Effectiveness (O) ++ ++

Process Versatility +(+) +(+)

Table 25: Indicative assessment of criteria for emerging alternatives in the PU Integral Skin Sector

There are no fundamental barriers to the introduction of the emerging technologies, although pilot 

projects on the pre-blending of HCOs in polyols will be necessary. There have been some concerns in 

the past about the implications of the limited supplier base and access to intellectual property, 

although these have been largely addressed. However, the biggest challenge to the replacement of 

any remaining use of ozone depleting substances will be the roll-out of these technologies on a 

sufficiently widespread basis. If the widespread introduction of HCOs can be successful, there is 

likely to be the gradual replacement of both saturated HFCs (HFC-134a and HFC-245fa) and 

CO2(water) blown technologies. The replacement of saturated HFCs, will certain deliver some 

additional climate benefits. 

Non-Article 5 Parties

In this non-insulating sector, CO2(water) technologies play a significant role, particularly where 

skinning properties are not critical. However, in non-Article 5 regions, hydrocarbons have become 

increasingly accepted as reliable replacements for HCFCs that were used previously. There has been 

some small use of HFCs (typically HFC-134a or HFC-245fa), but this has been limited to specialist 

applications. 

Article 5 Parties

Since the focus on technology optimisation has not been so prevalent in Article 5 regions except 

where multi-national clients (e.g. the automotive sector) have been involved, there has been a 

tendency to remain with HCFC technology while awaiting further developments. Transitions to highGWP HFC alternatives remain the easiest technology option, although methyl formate and methylal 

are also appropriate options, which mitigate at least some of the flammability risks associated with 

other hydrocarbons. The Business-As-Usual scenario follows the path and timing of most current 

HPMPs in predicting the transition paths and timing. 
34 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Extruded Polystyrene Foam 

Extruded polystyrene board is unique amongst the foam sectors considered in this report in that it is 

blown exclusively with gaseous blowing agents. This is a consequence of the extrusion process. 

Extruded polystyrene (XPS) should not be confused with expanded polystyrene (EPS – also 

sometimes called ‘bead foam’) which uses pre-expanded beads of polystyrene containing pentane. 

EPS has never used ozone depleting substances and is seldom addressed in UNEP Reports for the 

Montreal Protocol. XPS is used primarily as a building insulation and often competes with PU 

Boardstock. Its particular competitive advantage is in relation to its moisture resistance, which 

makes it especially useful for under-floor insulation and cold storage applications. There is another 

form of XPS known as ‘Sheet’ which is typically used for non-insulating applications such as leisure 

products (e.g. surf boards) and packaging materials. XPS sheet exited from CFC use early in the 

history of the Montreal Protocol and has used hydrocarbons almost exclusively ever since. 

Commercially available alternatives to ODS

Table 26 illustrates the commercially available alternatives in the extruded polystyrene sector: 

HCFC REPLACEMENT OPTIONS FOR XPS FOAM

SECTOR/OPTION PROS CONS COMMENTS

Extruded Polystyrene Foams 

Butane

Low GWP Highly flammable

Low operating costs Low thermal performance

HFC-134a/HFC-152a

Non-flammable High GWP (but lower than 

HCFCs replaced)

Good foam properties, 

especially thermal 

performance

Medium/high operating 

costs

CO2 /Ethanol/DME

Low GWP, low unit cost Small operation window Difficult to process especially for 

more than 50mm thickness board 

Non-flammable Flammable co-blowing 

agent

Need ethanol and DME as coblowing agent 

Table 26: Assessment of selection criteria for ODS alternatives in the XPS Foam Sector

As described earlier in this section, these three alternatives describe the primary options available in 

each of the three main non-Article 5 regions of the world. It should be noted that blends of 

saturated HFCs (HFC-134a/HFC-152a) are substantially used in North America and, to a lesser extent, 

in Europe, primarily by smaller producers who do not have the access to CO2 technology. Where 

they are used in Japan, they serve markets that cannot accept the flammability of hydrocarbon 

solutions. The assessment of these blowing agents via the criteria of this report is shown in Table 27: 

 butane HFC-134a/

HFC-152a

CO2 with ethanol 

or DME

Proof of performance ++ +++ ++

Flammability --- +++ ++

Other Health & Safety 0 + +

Global Warming +++ -- +++

Other Environmental - 0 0

Cost Effectiveness (C) -- ++ ---

Cost Effectiveness (O) +++ -- ++

Process Versatility ++ ++ +

 

Table 27: Indicative assessment of criteria for emerging alternatives in the XPS Foam Sector
35 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Emerging Alternatives

Table 28 sets out the most commonly cited emerging alternative for XPS Foam 

(b) HCFC REPLACEMENT OPTIONS FOR XPS FOAM

SECTOR/OPTION PROS CONS COMMENTS

Extruded Polystyrene Foams 

Gaseous unsaturated HFCs 

(HFOs) Low GWP High unit cost

At least three manufacturers (all in 

Europe)have now adopted this 

technology

Table 28: Emerging alternatives to ODS in the XPS Foam Sector

For all the reasons expressed in this section, there is considerable interest in the potential of 

unsaturated gaseous HCFCs/HFCs as either blowing agents or co-blowing agents with HCOs such as 

ethanol or dimethyl ether (DME). The technological solution has the potential of becoming a relative 

standard in the industry, but the key deciding factor in that respect will be the cost. This aspect is 

reflected in the criteria assessment below: 

HFO-1234ze(E)

Gaseous

Proof of performance +

Flammability ++

Other Health & Safety +

Global Warming +++

Other Environmental +

Cost Effectiveness (C) ++

Cost Effectiveness (O) --

Process Versatility ++

Table 29: Indicative criteria assessment for the major emerging alternative in the XPS Foam Sector

For the HCFC consuming market in China and elsewhere, the challenge is to decide whether there is 

a transitional option that moves to a low-GWP alternative before the availability of unsaturated 

HFCs such as HFO-1234ze (E) is secured. It is clear that hydrocarbons would have been an obvious 

option and that would have been a high priority for a number of producers in China operating under 

the HCFC Phase-out Management Plan there. However, in recent years, there have been a series of 

fires (mostly in the construction phase of major building projects) which have caused a reaction 

against organic insulation materials in general and XPS in particular. One of the underlying problems 

has been the inconsistency in use of flame retardants within XPS formulations, with recycled 

feedstock not being properly characterised in some instances. The XPS industry is making a strong 

case that properly formulated XPS board can be used safely throughout its lifecycle, but these 

developments have created a further barrier to the introduction of hydrocarbons as blowing agents 

at this sensitive time. 

The introduction of unsaturated HFCs will certainly avoid such a controversy, but the availability of 

such technology in Article 5 Parties is uncertain – particularly when the technology is yet to be 

commercially adopted elsewhere. There is also the unanswered question concerning the impact on 

cost. A temporary switch to saturated HFC blends could ensure that the Montreal Protocol 

objectives are met, but this will do little to benefit the climate when over 1 billion tonnes of CO2-eq 

could be avoided by a more benign solution. 
36 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Non-Article 5 Parties

Alongside PU Spray Foam, the extruded polystyrene sector represents one of the most challenging 

technological sectors of the market. Although CO2 technology has been successfully adopted by 

some of the multi-national producers, it is not very versatile and remains unsuitable for certain 

product types, even when modified with HCOs such as di-methyl ether. While hydrocarbons have 

proved uniquely acceptable in Japan, the majority of other non-Article 5 production is now based on 

the use of high-GWP HFCs such as blends of HFC-134a and HFC-152a. Attempts to move away from 

these blowing agents in the short-term are made less likely because of parallel concerns with the 

brominated flame retardants widely used in XPS and other polystyrene products. Accordingly, the 

Business-As-Usual scenario is relatively conservative in its outlook for further transition. 

Article 5 Parties

Extruded polystyrene manufacture has grown substantially in a number of Article 5 regions over the 

last 10 years. Much of the manufacture has been based on HCFC technologies, since these are the 

most versatile options for a wide range of processing scales. For China, in particular, there are a 

large number of small plants and although there is some hope that a specifically tailored CO2 

technology can achieve widespread conversion, the outcome of an important pilot study is still 

awaited. As with the non-Article 5 assessment, the Business-As-Usual scenario is relatively 

conservative and does not anticipate early transitions.

Phenolic Foam 

Phenolic foams are manufactured by a number of different processes, many of which shadow those 

already discussed for polyurethane foams. The largest markets for the product are as phenolic 

boardstock (manufactured by continuous lamination) and block foams, used primarily for fabricating 

pipe work insulation. Although the product made an entry into the North American market in the 

early 1980s, the particular technology was dogged with problems. As a result, there is little use of 

phenolic foam in that region today. However, successful phenolic boardstock technologies emerged 

in both Europe and Japan, with sales of the product continuing to grow, not only because of overall 

increases in the demand for thermal insulation, but also because of gains in market share. Phenolic 

foam’s main competitive advantage rests in its intrinsic fire and smoke properties. However, since it 

is made by an emulsion process, it also offers smaller cells which result in improved thermal 

performance. More recently, the product has begun to emerge on the Chinese market - in part as a 

response to concerns over recent fires. 

The use of phenolic foam as pipework insulation also stems from the intrinsic fire and smoke 

properties of the product and the growth of the product’s use has been particularly strong in regions 

where internal fire regulations are strict or where the high rise nature of construction requires 

additional fire precautions. 

Commercially available alternatives to ODS

Table 30 sets out the commercially available alternatives for the phenolic foam sector: 

HCFC REPLACEMENT OPTIONS FOR PF FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Continuous processes (including flexibly-faced lamination and pipe section manufacture)

n- pentane/iso-pentane 

Low GWP Highly flammable High incremental capital cost

Low operating costs Industry standard

Good foam properties

HFC-365mfc/277ea Non-flammable High GWP

Good foam properties High operating costs 

2-chloropropane

Low GWP Negligible ODP 

Non flammable
37 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

Block foams for various applications including panels, pipe insulation section, etc

HFC-365mfc/277ea

Non-flammable High GWP Low conversion costs

Good foam properties

High operating costs but 

improved by using mixed 

HFC/ CO2 (water)

Table 30: Assessment of selection criteria for ODS alternatives in the Phenolic Foam Sector

The lack of low-GWP alternatives for discontinuous block foams signals the need for further work in 

this area. However, the ranking of these options against the report criteria can be summarised as 

follows:

n-pentane

i-pentane

2-chloropropane HFC-365/227ea

Proof of performance +++ +++ +

Flammability --- 0 ++

Other Health & Safety 0 0 +

Global Warming +++ +++ ---

Other Environmental - 0 0

Cost Effectiveness (C) --- - ++

Cost Effectiveness (O) +++ + --

Process Versatility ++ + ++

Table 31: Indicative assessment of criteria for emerging alternatives in the Phenolic Foam Sector

Emerging Alternatives

As with other sectors, there is considerable focus on the potential of unsaturated HFCs/HCFCs. 

HCFC REPLACEMENT OPTIONS FOR PF FOAM FOR BUILDING/ CONSTRUCTION APPLICATIONS

SECTOR/OPTION PROS CONS COMMENTS

Continuous processes (including flexibly-faced lamination and pipe section manufacture)

Unsaturated HFC/HCFC liquids

Non-flammable Low conversion costs Successfully trialled and now 

Good foam properties High operating costs pursuing re-standardisation

Block foams for various applications including panels, pipe insulation section, etc.

Unsaturated HFC/HCFC liquids

Non-flammable Low conversion costs

Successfully trialled and now 

Good foam properties High operating costs pursuing re-standardisation

Table 32: Emerging alternatives to ODS in the Phenolic Foam Sector

One drawback for the adoption of this technology in phenolic foam is that there is no CO2(water) coblowing to offset some of the cost. Another option might be to use unsaturated HFCs/HCFCs as 

components of blends with hydrocarbons or other blowing agents. However, care will need to be 

taken with discontinuous block foams to avoid process flammability issues. Even if the technical 

hurdles are overcome, the investment case may not be compelling for the transition out of saturated 

HFCs in the discontinuous block foam sector in view of the small quantities consumed. It may require 

market pressure on the continued use of saturated HFCs or evidence of significant thermal 

performance improvements to provide additional support for the next transition step. 

Table 33 summarises the current status of these emerging options with respect to phenolic foam.
38 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

HFO-1336mzzm(Z) HFO-1233zd(E)

liquid Liquid

Proof of performance 0 -

Flammability +++ +++

Other Health & Safety + +

Global Warming +++ +++

Other Environmental + +

Cost Effectiveness (C) ++ ++

Cost Effectiveness (O) -- --

Process Versatility +(+) +(+)

Table 33: Indicative assessment of criteria for emerging alternatives in the Phenolic Foam Sector

Non-Article 5 Parties

The technologies in use in non-Article 5 regions are almost universally based on hydrocarbon or 2-

chloropropane blowing agents, since it has been found that the intrinsic fire properties of phenolic 

foams are more than sufficient to compensate for any blowing agent contribution to flammability. 

The only potential future transition might be to take advantage of the improved thermal properties 

of unsaturated HCFCs/HFCs, although this has not been postulated in the Business-as-Usual scenario 

for phenolic foam. 

Article 5 Parties

There is very little production of phenolic foam in Article 5 regions with the exception of China. In 

keeping with the bulk of phenolic foam manufacture in non-Article 5 countries, all know production 

in China is already based on hydrocarbon technologies.
39 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

7. Update on Bank Estimates and Emerging Management Strategies 

Estimated size of current Blowing Agent Banks and predicted growth to 2020 

Global banks of blowing agents in foams have been previously estimated to have grown from around 

3 million tonnes in 2002 to an estimated 4.45 million tonnes (inclusive of hydrocarbons) in 20155. 

Consumption is typically outstripping emissions by around 250,000 tonnes/year, implying that banks 

of blowing agents will grow to well in excess of 5 million tonnes by 2020. However, a significant 

proportion of this bank will already have moved into the waste stream (typically landfill) by that time 

as installed foam products reach the end of their respective service lives. Figure 5 shows how this 

flow into the waste stream might vary by foam sector based on anticipated product lifetimes.

Figure 5: Variation in the size and timing of blowing agent waste flows

Identifying Blowing Agents in the Waste Stream and other Waste Management challenges 

Once in the waste stream, such banks are broadly unreachable and the environment needs to rely 

on natural mechanisms such as anaerobic degradation to avoid the worst impacts of eventual 

blowing agent emission. Increasingly, ODS-containing foam is being treated as hazardous waste in a 

number of regions in an effort to avert uncontrolled landfilling, but the over-riding challenge is to be 

able to police shipments sufficiently well to avoid the practice when there is no simple way of 

determining the identity of the foam blowing agent routinely. The search for such detection 

equipment continues, since it would not only allow for the characterisation of waste, but would also 

assist customs officials on cross-border trade of foam products where blowing agent restrictions 

may already be in force. 

Assigning value to Blowing Agent recovery and likely impact on trends going forward 

A further option for limiting the quantity of ODS-containing and other high GWP blowing agent

foams going to landfill is to encourage voluntary intervention at the point of decommissioning by 

assigning value to the recovery and destruction of the foam or its blowing agent. At present, this 

value is most likely to arise from the climate benefits associated with the activity. However, an 

additional point of concern is that the average global warming potential (GWP) of the waste stream 

 

5

Data adapted from Special Report on Ozone and Climate (2005)
40 | P a g e 2 0 1 4 F T O C A s s e s s m e n t R e p o r t

will decrease with time as the very high GWP blowing agents (e.g. CFCs) become less prevalent. 

Figure 6 illustrates how this can happen: 

 Figure 6: Expected decline in average GWP of the waste streams for typical foam applications 

These trends imply that it is preferable to introduce effective waste management practices in the 

period prior to 2030 for PU Spray Foam. However, more importantly, they indicate that much of the 

climate benefit arising from the management of appliances foams has already passed. This is being 

borne out in practice for many appliance recycling plants, where the associated climate benefit 

cannot now be relied upon as a justification for investment. The consequence is that waste handling 

companies are looking to minimise their upfront investment costs in equipment and manual 

dismantling practices are becoming increasingly common for foam separation, even though there 

are associated emissions. This is especially the case in areas of low population density, where the 

economies of scale are more limited. 

Best Practice in the management of Insulation Foams and the importance of Segregation

Figure 7 provides a schematic diagram of the lifecycle of an insulation foam, illustrating the points at 

which blowing agent releases are likely. Since most new production and installation is now taking 

place with non-ODS blowing agents, the focus of ODS emission minimisation is at the point of 

decommissioning and thereafter. The effectiveness of this whole process is measured by the 

Recovery and Destruction Efficiency (RDE). The ability to maximise RDE lies in the degree to which 

insulation foams being decommissioned can be separated and segregated from other building 

demolition waste. The level of waste segregation varies substantially by jurisdiction and those with 

high levels of segregation achieve the best results in ODS recovery/destruction at lowest incremental 

cost. 

The choice exists to either directly incinerate the insulating foam or to shred it and recover the 

blowing agent for subsequent destruction. The latter approach is only really cost-effective where 

there are economic benefits from other components of the building element (e.g. steel from metalfaced panels). In Europe and Japan, where efforts to recover blowing agents have been most 

extensive to date, there is an increasing tendency to move to direct incineration in order to minimise 

cost, although this depends largely on the availability and permissibility of use of Municipal Solid 

Waste Incinerators. 
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Figure 7: Schematic of Emission Sources and Blowing Agent Management Options for Insulating Foams (Source: SKM Enviros/Caleb)
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8. Membership of the Foams Technical Options Committee

The following list represents the members of the Foams Technical Options Committee who have 

contributed to the content of this Report through the assessment period. 

Country Expertise Affiliation

Co-chairs Paul Ashford UK Phenolic Anthesis-Caleb

Miguel Quintero Colombia PU Ind Consultant

Members Terry Armitt UK Machinery Ind Consultant

Samir Arora India PU Systems Urethanes 

Roy Choudhury US Blowing Agent Foam Supplies

Rick Duncan US PU Spray Spray Foam Alliance 

Mike Jeffs UK PU Ind Consultant

Rajaran Joshi India XPS Owens Corning

Ilhan Karaagac Turkey XPS Izocam AS

Candido Lomba Brazil PU Trade Assoc. Abripur

Yehia Lotfi Egypt PU Systems Technocom

Joseph Lynch US Blowing Agent Arkema

Simon Lee US XPS Dow

Christoph Meurer Germany Blowing Agent Solvay

Sascha Rulhoff Germany Blowing Agent Haltermann

Enshan Sheng China PU Huntsman

Koichi Wada Japan PU Trade Assoc. JUII

Helen Walter-Terrinoni US Blowing Agent Du Pont

David Williams US Blowing Agent Honeywell

Allen Zhang China XPS Ind Consultant