Overview of 

Spray Polyurethane Foam Systems

CPI-SPFA 

Do-It-Yourself Yourself Workgroup Workgroup

December 1, 2009

Dial: 1-800-691-0264, Passcode: 273290

9:30 a.m. – 11:15 a.m. EDT
Agenda

• Welcome & Introductions (Neeva-Gayle Candelori & Chris Bloom)

– Webinar Scope

– Webinar Goals

• Overview of SPF Systems (Mark Spence)

2

• Overview of SPF Systems (Mark Spence)

– Basic PU Chemistry

– Spray PU Foam Characteristics 

• Worker Health & Safety with SPF Systems (Mark Spence)

– Worker Exposure Monitoring

– PPE Guidance

– Applicability to DIY Uses

• Summary & Conclusions (Mark Spence)

• Discussion & Next Steps (Chris Bloom)
DIY Work Group

• DIY Work Group 

– Brief Background

– Scope

• Key Objectives for Webinar
DIY Work Group

For purposes of the DIY Work Group, we are generally saying a 

DIYer = Consumer

• DIY Work Group Objective

– To enhance the DIY users understanding of effective practices regarding the safe 

use and handling of SPF products.

Some Common Acronyms Defined:

OCF = One Component Foam

2KLP = Two Component Low Pressure Kits

2KHP = Two Component High Pressure Systems
DIY Work Group Scope

2KHP

Industrial

DIY Work Group Scope

Professional

Consumer 2KHP

OCF

2KLP
DIY Work Group: Scope Summary

Scope Summary:

• OCF products available to DIYers / Consumers

• 2KLP Kits available to both ‘professionals’ and DIYers / 

Consumers

---------------------------------------------------------------------------

• 2KHP Systems are not generally available (or marketed) 

to DIYers / Consumers 

– anecdotal information indicates that these systems are not being 

obtained by DIYers
DIY Work Group: 

Webinar Objectives

• Enhance understanding of PU Chemistry

• Provide a clear differentiation between SPF 

product types (with a focus on those available to 

DIYers / consumers)

– Review Phys-Chem attributes

– Review some existing monitoring information

– Review PPE guidance

• Clarify the potential ‘risk profile’ associated with 

SPF products available to DIYers / consumers 
Overview of SPF Systems
Basic PU Chemistry

• Polyurethane is formed by the mixing and 

reaction of two components:

– “A Side” “A Side” – diisocyanates diisocyanates

– “B Side” – polyol blend
Basic PU Chemistry
“A side” – Polymeric MDI (PMDI)

– A mixture of homologous compounds:

Basic PU Chemistry

• 45-55% MDI monomer (n=0):

– 90+% 4,4’- isomer

• 45-55% MDI oligomers (n=1,2,3...)

– 50% “tri-iso” or “3-ring” (n=1)

– 25% “4-ring” (n=2)

– 12% “5-ring” (n=3)
MDI Properties

Property MDI Monomer Polymeric MDI

Melting Point (°C) 40 5

Basic PU Chemistry

Boiling Point (°C) >300 >300

Vapor Pressure (Pa) 6.2x10-4 @ 20 °C 3.1x10-4 @ 20 °C 

Saturated vapor conc. 

(g/m3) 

64 @ 20 °C 32 @ 20 °C 
“B side” – Polyol Blend

• Properties of PU result from polyol structure, additives 

composition:

– Polyol (>60%) 

• (affects structure: e.g., linear vs. branching)

Basic PU Chemistry

– Blowing agents

• (low-boiling liquids, e.g., pentane, dimethyl ether, hydroflorocarbons; forms 

foam, determines foam characteristics)

– Fire retardants

• (modifies fire characteristics of foam)

– Surfactants

• (affects foam cell size, structure)

– Catalysts

• (tertiary amine or organo-metallic; stabilize reactants & accelerate reaction)
PU Terminology

• Cream Time – Mix of isocyanate & polyol (brown 

liquid) turns opaque tan (reaction begins)

Basic PU Chemistry

• Tack-Free Time – Foam surface no longer sticky; 

second layer of foam can be applied

• Cure Time – Maximum foam physical properties 

achieved
SPF System Characteristics

• Basic Categories:

– High-Pressure Pressure SPF systems SPF systems

• 2-component systems

– Low-Pressure SPF systems

• 2-component kits

• 1-component foam products
1-Component vs. 2-Component Systems

• 2-Component:

– Isocyanate and Polyol in separate containers

– Mixed 1:1 at time of application; 50% PMDI

• 1-Component:

SPF Systems

• 1-Component:

– Isocyanate and Polyol combined in one container at time of manufacture

– Mixed at slightly greater than 1:1 into container

– Forms NCO-terminated PU in container

– 5-15% PMDI in container as marketed

– Reaction completed at time of application by reaction with ambient 

moisture

– CO2 secondary blowing agent /propellant produced:

• 2(R - N=C=O) + H2O ---> R-N-C-N-R + CO2
SPF Delivery Systems

• Containers

– Refillable Cylinders:

• 2-component, Low-P only

SPF Systems

– Single-use Drums / Cylinders:

• 2-component only, High- & Low-P 

– Pressurized Cans / Single-use cylinders:

• 1-component only
SPF Delivery Modes

• Spray

– 2-component only, high & low pressure

– Product application: insulation, coating

SPF Systems

– Product application: insulation, coating

• Stream / Bead

– 1-component & 2-component, low 

pressure only 

– Product application: adhesive, sealant 
SPF Systems
Worker Health & Safety 

with SPF Systems
Worker Exposure Monitoring

• Species monitored: 

– MDI

– MDI & main oligomer (“3-ring”, n=1)

Exposure Monitoring

– MDI & main oligomer (“3-ring”, n=1)

• Occupational Exposure Guidelines

– OSHA: 200 g/m3 MDI (20 ppb; ceiling)

– ACGIH TLV®: 51 g/m3 MDI (5 ppb; 8-h TWA)
Sampler Types

– Coated Filter

Exposure Monitoring

– Impinger

– Impinger + filter
Iso Check Sampler

Exposure Monitoring
High-Pressure Spray Foam Worker 

MDI Exposures

10 studies, 240+task and shift samples

MDI Conc. 

(mean [range]; g/m3)

Exposure Monitoring

All samples 8-h TWA

Applicators 577 [5 – 2100] 320 [10 – 460]

Helpers 113 [0.1 – 408] 51 [1 – 308]

Exposure 

Guidelines

200 (ceiling)

OSHA PEL

51 

TLV®
Low-Pressure Spray Foam Worker 

MDI Exposures

5 studies, 41 personal (task) samples, 

68 area / source samples

MDI Conc. (mean [range]; g/m3)

2-component SPF 1-component SPF

Exposure Monitoring

*ND() = not detected @ (detection limit), 1⁄2 Detection Limit used for mean

2-component SPF 1-component SPF

Applicators 30 [ ND*(6) – 82 ] ND(6) [ ND(1) –ND(8) ]

Helpers 12 [ ND(6) – 36 ] n/a

Exposure 

Guidelines

200 (ceiling)

OSHA PEL

51 (8-h TWA)

TLV®
Low-Pressure SPF 

Exposure Study Details

• Lab application (4 studies)

– Spray onto cardboard / plastic

– In lab hood (fan off) or plant (general ventilation)

Exposure Monitoring

– In lab hood (fan off) or plant (general ventilation)

– Extreme-case simulation

• More foam applied over shorter period of time

• Source samples can be taken near point of application

• Application of insulation in home (1 study)
Exposure Studies: 2-Component 

Low-Pressure Kits

Study 1: Residential Wall Insulation Application (spray)

• Method: Impinger

Sample Type MDI g/m3 Mean

[range]

n* #ND

Exposure Monitoring

*n= # of samples; #ND = # of samples that were 

below limit of detection

Personal - Applicator 48 [16-82] 6 0

Personal – Helper

(3-10’ from Applicator)

16 [ND(6)-36] 6 1

Area – 15-30’ from Applicator 1.9 [ND(2)-4.1] 8 7
Exposure Studies: 2-Component 

Low-Pressure Kits (con’t)

Study 2: Lab Application; Area samples at hood entrance (fan off) 

• 3 different single use kits used; 7-15 min application

• Methods: Impinger w/ backup filter, Filter

Sample Type MDI g/m3 Mean [range] n* #ND

Exposure Monitoring

Personal - Applicator 37 [13-66] 7 0

Area – Kit A (5 min use periods (3))

Crack filler / sealer - bead

4.9 [ND(7)-9] 4 3

Area – Kit B (5 min use periods (3))

Insulation – spray

55 [38-74] 3 0

Area – Kit C (full kit in 12 min)

Insulation - spray

130 1 0

*n= # of samples; #ND = # of samples that were 

below limit of detection
Impinger / Filter Comparison

• Side-by-side sampling done in Study 2 

(2-component low pressure SPF exposure study)

• 5 data points; Results: 

Exposure Monitoring

– Mean Impinger / Filter ratio = 1.7

– Range: 1.1 – 2.8
Exposure Studies: 2-Component 

Low-Pressure Kits (con’t)

Study 3: Lab Application 

• 2 different single use kits, 1 refillable system used

• 7-15 min application

Exposure Monitoring

• 7-15 min application

• Area samples: 

– near (1-3’)

– far (10-20’)

• Method: Iso Check filter sampler

– Dual filter, MDI & oligomers
Study 3 Results (con’t)

Sample Type MDI g/m3

;Mean [range] n* #ND

Personal -

Applicator

5.7 [ND(6)-13] [olig= ND(10)–10] 6 5

Area, Kit 1: 1-3’ 1 [olig=10] 1 0

Exposure Monitoring

10-20’

Adhesive: bead

ND(0.9) [olig=27] 1 1

Area, Kit 2: 1-3’

10-20’

Single-use kit: spray

ND(6)–17 [olig=ND(6)–20]

ND(1)–ND(6) [olig= ND(1)–ND(6)]

3

2

1

2

Area, Kit 3: 1-3’

10-20’

Refillable kit: spray

6-8.4 [olig=ND(10)–50]

ND(2)–ND(6) [olig= ND(1)–250]

2

2

0

2

*n= # of samples; #ND = # of samples that were 

below limit of detection
Exposure Studies: 1-Component 

Foam Products

Study 3,4,5: Lab Application 

• Adhesive, single use container; 11-24 min application

• Area samples at 1-20’, source ( 18”)

• Methods: Filter sampler (Study 3: IsoCheck; Studies 4,5: 13mm)

Exposure Monitoring

Sample Type MDI g/m3; Mean [range] n* #ND

Personal -

Applicator

ND(6) [ND(1) –ND(8)] 11 11

Area: Near (1-3’)

Far (10-20’)

ND(1) [olig=ND(6)] 

ND(0.9) [olig=ND(5)]

1

1

1

1

Area: Source 9.2 [ND(6) – 51] 15 13

*n= # of samples; #ND = # of samples that were 

below limit of detection
PPE Guidance for Applicators and Helpers
Applicability to 

Do-It-Yourself Uses

• Low-pressure products studied were:

– Representative of products for DIY use (2-component singleuse kits) 

– Representative of extreme Representative of extreme-case DIY use (1 case DIY use (1-component component 

foams)

• Professional products (single-use cylinders) used in 

exposure studies had higher PMDI content than 

consumer cans (13-15% vs. 6-11%)

• More material applied during sampling

• Respirator use not necessary for typical 1-component 

DIY application.
Summary & Conclusions

• Both 1- and 2- component low pressure foam products 

have significantly (~10x) lower worker MDI exposure 

profiles than high pressure foam systems.

• 1-component component foam products have significantly foam products have significantly lower 

exposure profiles than 2-component low pressure kits.

• Current PPE guidance for 1- and 2- component low 

pressure foam products provides adequate protection.

• Ongoing opportunity to provide enhanced outreach and 

education to DIY audiences regarding use and handling 

techniques – to be addressed in Tier 2. 
DIY Work Group : 

Webinar Objectives (re-visited) 

• Enhance understanding of PU Chemistry

• Provide a clear differentiation between SPF 

product types (with a focus on those available to 

DIYers / consumers)

– Review Phys-Chem attributes

– Review some existing monitoring information

– Review PPE guidance

• Clarify the potential ‘risk profile’ associated with 

SPF products available to DIYers / consumers 
General Risk Profile Comparison for 

SPF DIY Products 

Risk

2KLP

(spray)

PPE Sophistication

Potential

OCF

2KLP

(bead) Area of DIY WG 

focus going 

forward
Discussion