Page 1 of 16

ANALYSIS OF DUSTS COLLECTED DURING TRIMMING AND CUTTING OF

SPRAY POLYURETHANE FOAM (SPF)

Mark W. Spence Spence Consulting, LLC 1232 Holy

rood St. Midland, MI48640 Project Sponsored b y the Center for the Pol yurethanes Industry,

SPF Research Wor

k Group 16 March 2010Page 2 of 16

**ABSTRACT INTRODUCTION**  The primary

purpose of the study

was to establish sampling and anal yt ical techniques which would be appropriate and practical for further field evaluations of worker exposure during trimming and cutting of spray pol yurethane foam ( SPF ) . Because of this, this study employed a protocol under controlled laboratory conditions designed to simulate a trimming situation. This study is also an initial e valuat ion of the potential exposure of workers to inhalable and respirable dust and pol ymeric meth yl ene diphen yl diisocyanate (pMDI) during the post - application trimming and cutting of open cell and closed cell SPF insulation in interior applications. A cop y of the protocol for SPF application and trimming and samp ling and anal ys is is included in Appendix A of this report. This study

was conducted on December 14 - 15, 2009. On each day , SPF insulation was applied to sections of timber dry wall assemblies to simulate actual interior wall application. Extra spray

wa s applied so that the resulting foam extended well past the studs to provide adequate foam for extended trimming and cutting times. T he wall sections were set aside for 1 - 2 hours before being trimmed to ensure that the SPF was in the “cured” form most lik ely to produce particulate when cut or trimmed. P ersonal exposure sampling and source air sampling was conducted during trimming and cutting . **EXP E**  **RIMENTAL Facilit** **ies** This study

was condu cted in the Machine Hall of the Huntsman Advanced Technical Center , 8600 Gosling Road, The Woodlands, Texas 77381. SPF was applied in a ventilated spray

booth equipped with a water cascade which was located in the Machine Hall. Trimming and cutting of the SPF was conducted in an environmental chamber within the Machine Hall . The spray booth and environmental chamber were located approximately

40 feet from each other. **Foam Systems** Open - cell foam

– a nominal 0.5 pounds per cubic foot (pcf), pol yether pol yol - based poly urethane foam sy stem ty

pical of those currently

u sed in interior wall spray applications was used. Closed
- cell foam

– a nominal 2.5 pcf, polyester / polyether polyol - based rigid poly urethane foam sy stem ty

pical of those currently

used in interior and exterior wall and roof spray

applications was used. **SPF Application and Trimming** Page 3 of 16

SPF insulation of one foam ty pe (i.e. closed cell or open cell) was applied to multiple wall sections of timber drywall assemblies over about a 20 - minute period . The foams were applied using a Graco “Reactor H25” spray unit fitted with 50 feet of hose and using a Graco “fusion” spray gun. **NOTE:** Innormal field application, sufficient spray is applied to expand to approximately

the plane formed b y the face of the studs. Trimming and cutting is then conducted to clear the f

ace of the studs and bring any extra foam below the plane of the stud faces. In this study, e xtra spray was applied so that the resulting foam extended well past the studs over the entire wall section to provide adequate foam for extended trimming and cutting times , as shown in Figures 1 and 2 . After spraying, the wall sections were leaned against the wall in the Machine Hall in the vicinity of the environmental chamber and allowed to cure for approximately 40 minutes before trimming was conducted. SPF i nsulation in the wall sections were cut and trimmed flush with stud surfaces using each of the trimming techniques described below over a 60 - 80 minute period. The wall sections were used in the order in which they had been sprayed. Trimming was conducted in an environmental chamber (interior dimensions: 254 cm high, 284 cm wide, 325 cm deep) located in the M achine Hall . The chamber doors were open, but there was no additional ventilation beyond the general ventilation in the Machine Hall, which was 6 air changes per hour . Observations with a smoke tube in the environmental chamber showed only very

slight air currents in random directions. Temperatures and humidity inside the chamber during trimming and cutting were 71.6

– 73.0  F (22.0 - 22.8  C) and 41 - 46 %, respectivel y. Th e process of SPF wall section preparation, curing, and trimming was carried out four times to give duplicate trimming sessions with each foam ty pe where all trimming took place 1 - 2 hours after the foam was applied to the wall sections. TRIMMING TOOLS Foam Planer

– pneumatically- operated, wire - brush Tough Mechanics planer (planer brush: 9 cm diameter, 60 cm long) (Fig. 3) Sander

– Bosh 1028VSR hand - held electric drill with Norton “Stick and Sand” sanding disk (5” (12.7 cm) diameter) with Norton 40 grit sanding disk (Fig. 4) Hand Saw

– 36” x 1” (91 cm x 2.5cm) blade; 8 teeth per inch (Fig. 5) Hand Scraper #1

– Husky #482 526 “14 - in - 1” Paint Tool, 3” (7.6 cm) blade (Fig. 6 ) Hand Scraper #2

– Groomex #63306 dog shedding blade (Fig. 7 ) TRIMMING TECHNIQUE GROUPSPage 4 of 16

Trimming tools were grouped into “ high dust potential” and “low dust potential” categories for the foam type on which they might be used in actual SPF insulation application based on subjective understanding of the techniques . The resultin g groupings are shown in Table I .Page 5 of 16

**Table I . SPF**  **Insulation Trimming**  **Technique Groups Trimming T**  **echnique Dust Potential**  **Group Open Cell** 

**SPF Closed Cell** 

**SPF** Hand Saw low X n/a Foam Planer high X X Sander high n/a X Hand Scraper ( #1 & #2 ) low X X Trimming was conducted in duplicate 15 - 20 minute sessions (one on each day of the study) for each of the two trimming groups (high dust potential, low dust potential) for each SPF type (open cell, closed cell), as indicated in Table I . **Expos ure Monitoring**  During each trimming session, personal exposure monitoring on the worker doing the trimming was conducted for pMDI, inhalable particulate s , and respirable particulate s . In addition, inhalable particulate source sampling was conducted b y ho lding the sampler 12 - 24 inches from the trimming area. Samples were collected using SKC Aircheck 52 personal air sampling pumps. The sampling media was attached to the sampling pumps, the sampling pumps were flow calibrated using a Bios Dry - Cal DC - lite Model 717 - 01 calibrator , and the sampling media was located in the worker’s breathing zone or near the particulate source before each trimming session . Figure 8 shows the samplers in place as they were worn by

the worker. Source samples were held in the close vicinity (i.e., within 30 cm) of the point of contact between the trimming tool and the foam. Immediately

after each trimming session, the sampling devices were retrieved, flow checked, and the samples were prepared for anal ys is as described in the “Monitoring Techniques” section of this report . All s ampling equipment and sample analy sis was supplied by the Baye r Materials Science Environmental Anal yt ical Laboratory (BMSEAL) in Pittsburgh, PA , an AIHA - accredited laboratory . Background samples we re collected for pMDI, inhalable particulates, and respirable particulates before the start of trimming each day . The samples were collected for approximately

30 minutes in the center of the environmental chamber and were mounted on a tripod about 24” (60 cm) above the floor. SAMPLING AND AN A LYS IS TECHNIQUES Polymeric MDI To conduct sampling for pMDI , the outlet nozzle of a pre - loaded 13 - mm cassette was attached to the flexible tubing from the sampling pump to be used. The flow rate throughPage 6 of 16

the cassett e was set to approximately 2 L/min as specified in the method and recorded to a precision of two decimal places. Following sampling, the sample flow was again measured and recorded, and then the filter cassette was opened and the 13 - mm glass fiber filter was transferred using tweezers to a 4 - mLglass vial. Using a pipettor (Gilson Pipetman 0 - 5 mL adjustable), 2.0 mLof a 90:10 solution of acetonitrile (Honey well B&J high purity): dimethyl sulfoxide (Fisher lot 061838) was added to the vial. The vial was capped with a poly seal cap and shaken well. The cap was sealed with pressure tape and a numbered sample label applied to the vial. The vials were packed in a DOT - approved shipping container for return to BMSEAL for anal ys is. Samples were anal yz ed for pM DI concentrations according to Bayer Material Science Environmental Anal yt ical L aboratory (BMSEAL) M ethod 1.7.7 . The method is based on OSHA method 42, in which air is drawn through a glass fiber filter which has been treated with 1,2 - py

ridylpiperazine ( 1,2 - PP). Isocyanates react with the primary amine functional groups on the 1,2 - PP to form a stable derivative which serves as a sensitive anal yt e in subsequent liquid chromatography / ultraviolet detection (LC/UV) anal ys is . Poly meric MDI (pMDI) is a mixture composed of MDImonomers (45 - 55%) and a series of larger, multiple - phenyl - ring, multi - isocyanate homologues of MDI (45 - 55%) . Because characterized standards are only available for MDI and the pMDI mixture, the BMSEAL method employ s instrumental calibration for these two anal yt es. In the case of pM DI , the three - phenyl - ring triisocyanate homologue of MDI is used as the calibration peak for the entire mixture . Thus, pMDIvalues reported by this method include the MDI mass; to estimate the total mass of the multiple - phenyl - ring, multi - isocyanate MDI homologues in the sample, the MDI result may be subtracted from the pMDIresult . The method reporting limit was 0.1  g for MDI and 3  g for pMDI. The 1,2 - PP coated 13 - mm glass fiber filters were prepared b y the BMSEALand pre - loaded into poly prop yl ene cassettes. Two quality

assurance samples which had been spiked with known amounts of pMDI were prepared b y the BSEALlaboratory and included with the sampling equipment sent to the field. These samples were prepared in the field as if they had been field samples, following the desorption procedure described above and returned to the laboratory for anal ys is. In addition, two of the sampling filters were desorbed without having air drawn through them to serve as field blanks. Inhalable Particulate Inhalable particulate samples were collected and analyzed according to NIOSH Method 0500. The samplers used were IOM personal samplers, conductive plastic version (SKC Cat. # 225 - 70A ; Fig. 9 ). These samplers were o perated at the 2 L/min sampling flow rate specified in the instructions for the device. The sampler consists of a sample cassette,Page 7 of 16

which contain s the 25 - mm sample filter, and a housing, which connects to the sampling pump and into which the loaded sample cassette is placed (Fig 9) . The sampl e cassettes were loaded with 25 - mm PVC membrane filters (5 m pore size , SKC Cat. # 225 - 8 - 04) and pre - weighed as a unit by the anal yt ical lab. To conduct sampling, a loaded cassette was removed from its numbered trans port clip, placed in the bottom of the IOM housing, and the housing top screwed in place. The housing was then connected to the tubing from the sampling pump to be used; the flow was set to approximately

2 L/min (using calibration adapter SKC Cat. # 391 - 0 1) , and recorded to a precision of two decimal places. Following sampling, the sample flow was again measured and recorded, and then the sample cassette was removed from the IOM housing and replaced in the transport clip. A numbered sample label was appl ied and the sample was placed in a zipper bag for anal ys is. All handling of IOM sample cassettes was done using powder - free nitrile laboratory

gloves to avoid adding weight to the cassettes from fingerprints. Analy sis consisted of gravimetric determinati on of the mass captured b y the sample cassette ; the reporting limit was 200  g. Respirable Particulate Respirable particulate samples were collected and anal yz ed following NIOSH Method 600. P re - weighed 37 - mm PVC membrane filters (5 m pore size) in three - piece poly styrene cassettes (SKC cat. # 225 - 803) fitted with a GS - 3 condu ctive plastic cyclone pre - selector (SKC cat. # 225 - 100) were used as the samplers . Figure 10 shows a diagram of the assembled sampler. These samplers were operated at the 2.75 L/min flow rate specified in the method . To prepare sampling equipment, the t op section of a 37 - mm filter cassette assembly was removed and the GS - 3 cy clone was press - fitted onto the middle section of the cassette. The flow rate through the filter cassette / cyclone assembly was then set to approximately 2.75 L/min (using calibrat ion jar SKC Cat. # 225 - 111), and recorded to a precision of two decimal places. The calibrated filter cassette / cyclone assembly was mounted in a holder (SKC cat. # 225 - 1) to facilitate locating it in proper orientation in the worker’s breathing zone. F ollowing sampling, the sample flow was again measured and recorded, and then the GS 3 cyclone was removed from the filter cassette inlet and the pol ys ty rene cassette top was placed back on the cassette. A numbered sample label was applied and the sample w as placed in a zipper bag for anal ys is. The cyclone was wiped with a lint - free wipe and an y contents in the grit pot emptied to prepare it for reuse. Analy sis consisted of gravimetric determination of the mass cap tured b y the sample filter. The reportin g limit was 30  g.Page 8 of 16

Inorganic Particulate Following gravimetric analy sis, the membrane filters from both the inhalable and respirable particulate samples were placed in a pre - weighed crucible then the crucible with the filter in it was heated for two hours in a furnac e at 765  C. Following this, the crucible was c ooled and re - weighed . An y additional mass remaining in the crucible after heating was interpreted as “ash” (i.e., mass from inorganic particulate and therefore not attributable to SPF) . **RESULTS & DISCUSS ION**  **Observations** The subjective grouping of trimming techniques into “low dust potential” and “high dust potential” was supported by visual observations . The pneumaticall y- powered foam planer generated b y far the most observable foam particulate, follow ed b y the sander. None of the three hand techniques (saw, scraper #1, and scraper #2) generated noticeable airborne particulate; their use resulted primaril y in relativel y large pieces of foam which fell to the floor as they

were generated . When using the foam planer, the character of the particulate generated was quite different between closed cell and open cell foam. With open cell foam, planer use produced fluffy , snow - like particulate that adhered to surfaces, presumably as a result of static charge . In contrast to this, particulate produced b y planer and sander use on closed cell foam produced a much finer, powdery particulate which also adhered to surfaces. **Measurements** The detailed results of the air sampling conducted during SPF insulation tri mming are given in Table I I . Table II I summarizes the results for each trimming group. The anal yt ical laboratory

reports are included as Appendi ces B - 1 to B - 4 to this report. pMDI In all trimming groups with both foam ty pes, MDI and pMDI were not detect ed in the personal and source samples. This was true even in the case of the samples taken during the high dust potential techniques, where foam dust was observed inside the sampler after sampling and was included with the filter in the desorbed sample. The detection limit for these short - term task samples was a factor of at least 20 below the OSHA PELof 200  g/ m 3 (Ceiling) and a factor of at least 5 below the 8 - hour time - weighted average occupational exposure limit (ACGIH T LV ® for MDI = 51  g/ m 3 ).Page 9 of 16

Th e results of the pMDI quality assurance samples are reported in Table IV below. The samples were spiked with a solution containing 4.65  g pMDI which had specifications of 40 - 45% monomer (MDI). The results of the spikes showed 95 - 110% accountability for the pMDI amount spiked, and MDI monomer results which were 37 - 41%. These results demonstrate that the method was functioning as validated and could be expected to detect any pMDI that was present above the detection limit. IN HALABLE PARTICULATE The i nhalable particulate results largel y mirror the subjective observations reported above: the results are highest for the pre - identified high dust potential trimming techniques with both foam ty pes . The results for these short - term task samples were a facto r of about 30 above the occupational exposure limit concentration ( OSHA PEL= 15 mg/m 3 8 - hour TWA and the ACGIH recommendation for inhalable particulate, not otherwise specifi ed = 10 mg/m 3 ). The inhalable particulate results for the low dust potential tec hniques gave results below the 8 - hour time - weighted average occupational exposure limit concentration in the case of the open cell foam . However, the mean concentration for the low dust potential techniques with the closed cell foam had a mean that was al most 20 times higher. In this case, one of the two replicates had inhalable particulate results that were 25 times the first replicate ; this single result greatly skewed the mean . While the replicate trimming operations were done b y different workers, th ere were no differences observed in the way they did the trimming that would account for such a large difference in the sample results. Interestingly , this is the only trimming situation where the source inhalable particulate results were lower than the p ersonal inhalable particulate results. It is also interesting to note that the respirable particulate results were higher for the replicate with the lower inhalable particulate results. RESPIRABLE PARTICULATE The mean respirable particulate results fo r these short - term tasks were above the occupational exposure limit concentration ( OSHA PEL= 5 mg/m 3 8 - hour TWA, ACGIH respirable particulate, not otherwise specif ied = 3 mg/m 3 ; ) only

for the open cell foam, high dust potential techniques . Even so, the me an in this case exceeded the ACGIH concentration by

a factor of just 2.5. This result indicates that the particulate generated by all the trimming techniques is predominantly large. IN ORGANIC PARTICULATE Ashing of the PVC membrane filters from both th e inhalable and respirable samples gave results that ranged from - 9 to 0.9% ash. Since the range for four blank membrane filters that were ashed ranged from - 2 to 0.7% ash, this result indicates that all of the gravimetricall y measured mass was organic i n nature. This is the expected result if all the particulate captured resulted from SPF insulation. This information will be useful inPage 10 of 16

later field sampling at actual construction sites, where a significant portion of the airborne particulate may

result f rom non - SPF sources such as concrete and sheetrock. The ashing differential determination is designed to be a simple way to estimate the proportion of the mass measured that is not attributable to SPF. **CONCLUSIONS** The following conclusions can be drawn from the results in this study :  The sampling and anal yt ical techniques used appear to be practical and adequatel y sensitive for use in field evaluations of SPF insulation trimming exposures.  While the SPF insulation trimming operations in this study were designed to simulate e xtreme case field situation, p MDI was not detected in an y of the samples, indicating that exposure to these SPF components from trimming is not likely to be a concern when trimming is conducted with at least one hour cure after appli cation.  The inhalable particulate results were greater than the relevant occupational exposure guideline in all but one case, while the respirable particulate results were under the relevant occupational exposure guideline in most cases . The use of resp iratory

protection appropriate for particulates is indicated during SPF trimming operations.Page 11 of 16Page 12 of 16Page 13 of 16 Page 13 of 16Page 14 of 16 

### Appendix A **Protocol 1 :**  **DUST & MDI**  **MEA SUREMENTS**  **DURING TRIMMING OF**  **SPRA YED**  **POLYURETHA NE**  **FOA M**  **INSULA TION**  **Objective** Evaluate the potential exposure of workers to inhalable and respirable polyurethane (PU) dust and pMDI during the post - application trimming / cutting of half pound open cell & two pound sprayed PU foam insulation (SPFI) in interior applications. 1. P ersonal samples (within 30cm of the breat hing zone) will be collected for total inhalable particulates (TIP) , respirable particulates (RP) & pMDI on workers involved in cutting and trimming sprayed PU foam insulation to evaluate worker exposure potential. 2. Source samples (within 30 cm of the area being trimmed and downwind of it) will be collected for TIP to measure the maximum concentrations of particulates produced by the trimming. 3. Sampling times will be as long as is reasonably practical (to increase sensitivity) and will be representative of th e work practices undertaken by workers trimming sprayed PU foam insulation . 4. Target quantitation limits – inhalable / respirable dust: 1  g/m 3 , isocyanates: 5  g/m 3

. **SPFI Trimming Experimental Procedure & Sampling Plan**  1. The experiment will be carried out in an SPFI development laboratory situation so that conditions can be controlled a. No experiments will take place at least 24 hours before t he experiment in same room and no experiments will take place during the test which could interfere with the tests. b. Local exhaust ventilation will not be used. c. Temperature, relative humidity, room air changes per hour, and room air current direction in the vicinity of the trimming will be recorded. d. The application and trimming operations will be videotaped for documentation and explanation purposes e. Area background (blank) samples (TIP, RP, pMDI) will be taken facing the room air current a few meters away from the operation before the SPFI is applied. 2. SPFI (a representative 1⁄2 lb or 2 .5 lb formulation) will be applied to a model wall section using normal commercial application techniques and application rates . The SPFI formulation and application conditions w ill be chosen to produce foam with the highest potential to generate dust. The SPFI will be applied in such a way that post - application trimming will be needed. 3. After a curing time of 1 - 2 hours, the foam will be trimmed using each applicable trimming tech nique (see table below ) . The techniques will be grouped into “low dust potential” and “normal dust potential” for each type of foam; a total trimming time of at least 15 minutes will be used for each dust potential technique category . T he duration of use of each technique will be recorded. **Trimming Technique Dust**  **Potential 1⁄2 lb (Open** 

**Cell) SPFI 2.5 lb (Closed** 

**Cell) SPFI** Foam Knife low X n/a Foam Planer normal X X Grinder / Sander normal n/a X Hand Scraper (e.g., putty knife, curry comb, ice spud) low X XPage Page 15 of 16 4. A single personal sample of each type (TIP, RP, pMDI) will represent composite exposure during all the trimming operations for each dust potential category with the SPFI wall section. 5. A single source sample (TIP) will represent composite particulate concentration during all the trimming operations for each dust potential category with the SPFI wall section 6. Steps 2 - 5 will be repeated with the same SPFI formulation as a replicate. 7. Steps 2 - 6 will be repeated with the remaining SPFI formulation. Sa mpling Plan Summary Sample Background Total (2 foams) Ty pe Normal Dust Low Dust Normal Dust Low Dust TIP 1 2 2 2 2 **17** RP 1 2 2 **9** MDI 1 2 2 **9** Background: **3** Source: **8** Personal: **24 35**  Source Personal

Each Foam , in duplicate

**Sampling & A naly** **tical Methods P**  **articulates (TIP & RP)**  1. TIP samples will be collected using IOM samplers equipped with appropriate membrane filters. 2. RP samples will be collected using appropriate membrane filters equipped with cyc lonic pre selectors operated at the flow rate to give the appropriate cutpoint. 3. The concentration of particulate deposited on the filters will determined gravimetrically using a microbalance. 4. Following the gravimetric determinations, the organic content of the collected particulate will be determined by ashing the filters, weighing the residue, and subtracting the residue weight from the original gravimetric weight . 5. Particulate sampling will be carried out in accordance with international standards, e.g. : a. ISO 15767:2009 - Wo rkplace atmospheres. Controlling and characterizing uncertainty in weighing collected aerosols b. MDHS 14/3 - General methods for sampling and gravimetric analysis of respirable and inhalable dust. c. CEN/TR 15230 - Wo rkplace atmospheres - Guidance for sampling of inhalable, thoracic and respirable aerosol fractions **Poly meric MDI (pMDI)**  1. pMDI samples will be collected using 13 - mm samplers equipped with binder free GF filter impregnated with an appropriate derivatising reagent, e.g., 1,2MP , 1,2 - PP, or MAP 2. After sampling, filters will be immediately desorbed in the field and returned to the laboratory for analysis.Page Page 16 of 16 3. A ll samples will be analysed for monomeric MDI and MDI trimer using liquid chromatography 4. pMDI sampling will be carried out in accordance with methods currently used by MDI producers in the US.