Open Cell Monitoring, a Follow-up After Reformulation · In this follow up study, after reformulation of the catalyst package, the half-pound open cell SPF formulation, was applied

©2015 American Chemistry Council

Open Cell Monitoring, a Follow-up After Reformulation

WILLIAM ROBERT

BASF Corporation 1609 Biddle Avenue, Wyandotte, MI 48192

JAMES ANDERSEN

BASF Corporation, 13630 Watertower Circle, Minneapolis, MN 55441

RICHARD WOOD

Air Products and Chemicals, Inc. 7201 Hamilton Boulevard Allentown, PA 18195-1501

ABSTRACT

A paper entitled “Spray Polyurethane Foam Monitoring and Re-Occupancy of High Pressure Open Cell Applications to New Residential Constructions” was presented at the 2014 CPI Conference in Dallas, Texas where industrial hygiene air monitoring was conducted during the application of open cell spray polyurethane foam (SPF) in residential homes. The results of the study indicated residual amine catalyst was found 24 hours after application at concentrations above any recommended occupational exposure limit (OEL) for the catalyst. In a follow-up study presented in this paper, the open cell formulation was modified to replace the emissive catalyst with a non-emissive or reactive catalyst. Components measured during application included the new non-emissive catalyst, MDI and flame retardant. Additional monitoring for MDI, flame retardant, and amine catalyst was also conducted during trimming of the overspray foam (two hours after application) and twenty four hours after application in the homes. Validated air sampling and analytical methods were followed for these studies.

In the previous paper, the amine catalyst results were verified through work at the BASF Research and Training Center in Houston, TX under controlled conditions during the trimming of freshly sprayed foam as well as foam aged one day to one week following application without ventilation. The ventilation was not used to simulate worst case scenario and ensure that any emission was captured by our monitoring method. BDMAEE (Bis-(2-Dimethylaminoethyl) ether) catalyst concentrations exceeded recommended OELs during trimming activities in the absence of mechanical ventilation. Though it is industry best practice for workers to consider a combination of engineering controls including, but not limited to, mechanical ventilation, the previous study was designed as a worst-case scenario therefore, under controlled study environment, mechanical ventilation was omitted. Following the controlled laboratory study, the SPF system was reformulated using non-emissive catalysts.

In this follow up study, after reformulation of the catalyst package, the half-pound open cell SPF formulation, was applied at the BASF Research and Training Center in Houston, in a large warehouse and in a residential home under construction. To simulate worst-case scenario and to ensure capture of emissions no mechanical ventilation was used during the study. Natural ventilation, through open windows and doors typical of new residential construction applications, was utilized. Airborne concentrations of MDI, flame retardant, amine catalyst, and total VOCs were evaluated during and after application of SPF. At the BASF Research and Training Center, using the same study protocol of cutting and trimming of foam, resulted in the non-emissive amine catalyst concentrations below analytical detection limits. Industrial Hygiene monitoring (SPF application in a large open building) of the amine catalysts were also below detection limits for the applicator, 15 feet and 30 feet from the application. MDI and TCPP were also extremely low. Also, SPF application in a new home under construction, personal samples resulted in amine catalysts below detection limits. TCPP and aldehydes were also extremely low. There have been suggestions that formaldehyde may be generated during the polyurethane reaction of spray foam. The results clearly do not show this. All were at background concentrations.

Follow up work conducted in October 2014 (warehouse) and March 2015 (home)

As a result of previous open cell industrial hygiene monitoring, the open cell formulation was modified to replace the emissive catalyst with a non-emissive, or reactive catalyst. Components measured during application included the new non-emissive catalyst, MDI, flame retardant and aldehydes. Additional monitoring for the same components


were also conducted during trimming of the overspray foam (two hours after application) and twenty four hours after application, and in the field at a warehouse and new home under construction. Validated air sampling and analytical methods were followed. BACKGROUND The sampling plan was designed to collect and measure major chemical ingredients contained in the liquid A and B compounds and to determine if any SPF chemical components become airborne during and after application. SPF chemicals monitored include: MDI (2-ring and 3-ring) the A side component; TCPP, a flame retardant, total volatile organic hydrocarbons (TVOC – a scan of solvents and odoriferous compounds that may be present in indoor air per EPA method TO-15), aldehydes and amine catalysts. The typical finished open cell half pound density SPF foam is field manufactured when the liquid “A” side and the liquid “B” side are combined though special high pressure heated airless spray application equipment. The “A” side or specific chemical called polymeric methylene diphenyl diisocyanate (PMDI), contains approximately equal amounts of monomeric MDI (4,4-MDI, a two ring structure) and higher molecular weight oligomers of MDI (three, four and five ring structures). The “B” side is a blend of predominantly polyol, with flame retardants, catalysts, and surfactants.

Table 1: SPF Chemicals Selected for Post-Spray Evaluation After Reformulation Liquid A – Side Compound

Chemical Common Name Occupational Exposure Limit Polymeric methylene diphenyl diisocyanate PMDI Not Established

Monomeric methylene diphenyl diisocyanate 2, 4 - MDI and 4,4 - MDI 0.005 ppm

Liquid B – Side Compound Tertiary Amine Catalysts N-[2-(dimethyl amino) ethoxy] ethyl]-N-methyl-1,3-propanediamine N,N,N,-Trimethylaminoethylethanolamine

DMAEEMPDA

TMAEEA

Not Established

Not Established

Fire Retardant Tris-(1-chloro-2-propyl) phosphate

TCPP

Not Established

Total Volatile Organic Chemicals TVOV Not Established Aldehydes Formaldehyde* 0.75 ppm TWA

0.5 ppm Action limit * Formaldehyde was selected for monitoring because it may be generated during the reaction process; not added to the product. The Occupational Safety & Health Administration (OSHA) specifies a ceiling limit for MDI of 20 parts per billion (ppb), equivalent to 0.2 mg/m3. This is the exposure concentration which should never be exceeded without respiratory protection. The American Conference of Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) guideline for MDI is 5 ppb as an 8-hour Time-Weighted Average (TWA). The current OEL for MDI applies only to the 2-ring monomeric MDI (Diphenylmethane-4,4’-diisocyanate CAS # 101-68-8). The MDI that is used in the SPF industry is a polymeric version of MDI, which contains monomeric MDI as well as other higher ring isomers of MDI. The combination of the 2-ring and 3-ring MDI isomers typically constitutes approximately 80% of the total MDI isomers contained in polymeric MDI. Some manufacturing processes can generate aerosols that result in a greater potential for exposure to the 3-ring isomer. Therefore, for the purposes of providing a more accurate assessment of MDI exposure and body burden to the active metabolic


isocyanate functional group, we report the 2-ring, 3-ring, and total MDI. For regulatory compliance purpose, the OEL is applied to only the 2-ring MDI. However, BASF recommends and encourages customers to evaluate and develop a MDI control program based on the combination of the 2-ring and 3-ring isomer. There is no OSHA permissible exposure limit (PEL) nor ACGIH Threshold Limit Value (TLV) guideline for the flame retardant, Trichloropropyl phosphate (TCPP) The amine catalysts were N-[2-(dimethyl amino) ethoxy] ethyl]-N-methyl-1,3-propanediamine (DMAEEMPDA) and N,N,N- Trimethylaminoethylethanolamine (TMAEEA). There are no established OSHA PEL’s for the amine catalysts monitored during this survey. There have been no inhalation studies that conclusively establish concentrations which workers can be repeatedly exposed day after day without adverse effect for N-[2-[dimethyl amino) ethoxy] ethyl]-N-methyl-1,3-propanediamine (DMAEEMPDA) or N,N,N- Trimethylaminoethylethanolamine (TMAEEA). Aldehydes and more specifically, formaldehyde, was measured. Formaldehyde has an OSHA TWA limit of 0.75 ppm with an Action limit of 0.5 ppm. In addition to common raw materials, the levels for certain VOCs were also monitored. No OEL have been set for VOCs in non-industrial settings. ANALYTICAL TECHNIQUES AND METHODS MDI SKC AirChek 2000 air sampling pumps were used to collect area samples of MDI aerosol and vapor. The pumps were calibrated to a flow rate of 1.0 L/minute with a BIOS DC Lite (S/N 100615) flow calibrator before and after sampling. The average flowrate was used to calculate air volumes unless otherwise noted. The MDI samples were collected in 15 mls of 1-(2-pyridyl) piperazine (1,2-PP) in glass impingers with a backup 13 mm glass fiber filter, impregnated with 5 mg of 1-(2-pyridyl) piperazine (1,2-PP). Impingers were changed to keep sample times less than four hours. After samples were collected, the filter was removed from the cassette with tweezers and placed in a vial. Two milliliters of 90% acetonitrile and 10% dimethyl sulfoxide solution (DMSO) with 1,2-PP were rinsed through the front tapered section of the filter cassette to flush dust on the inside of the cassette into the vial containing the filter. The vial was hand agitated to ensure the particulate on the filter was completely wetted by the acetonitrile/DMSO solution. The vials of acetonitrile/DMSO solution with filters, along with a blank filter in a vial of solution, were shipped to the BASF lab in Wyandotte, Michigan. The samples were analyzed following a modified version of the National Institute for Occupational Health (NIOSH) 5521 Method at an American Industrial Hygiene Association (AIHA) accredited laboratory. The deritivization solvent used was 1,2 PP instead of 1, 2 MP = 1-(2-methoxyphenyl) piperazine as noted in NIOSH Method 5521 because the lab is much more familiar with this solvent. To ensure there was no breakthrough of MDI, a backup filter was used as described in NIOSH Method 5525. The concentration of MDI reported in ppb, includes MDI vapor and MDI associated with foam particles. To assess the potential health impact of polymeric MDI, the concentration of two plus three ring MDI was also calculated for comparison to the OEL. Triethyl Phosphate (TCPP) SKC AirChek 2000 air sampling pumps were used to collect area samples of TCPP vapor. The pumps were calibrated to a flowrate of around 1.0 L/minute with a BIOS DC Lite (S/N 100615) flow calibrator before and after sampling. The average flowrate was used to calculate air volumes unless otherwise noted. Samples were collected on a XAD-7 OVS tube (glass fiber filter, 13-mm; XAD-7, 200mg/100mg) per NIOSH Method 5523. The XAD-7 OVS tubes, along with a blank tube, were shipped to the BASF lab in Wyandotte, Michigan. The samples were analyzed following NIOSH 5523 Method at an AIHA accredited laboratory. The concentration of TCPP was reported as ppm (and) mg/m3.


Amine Catalyst Monitoring Methods Two amine air sampling methods were used for portions of the study. Samples collected during the application of residential SPF were obtained using standard field monitoring procedures. A second method having greater analytical sensitivity was used in the spray booth to evaluate catalyst emissions during the trimming of aged SPF. Air samples collected during SPF application in the warehouse and the home for amine catalyst evaluation were collected by drawing air through tubes containing XAD-2 sorbent material with calibrated Gillian low flow pumps. Following collection, the samples were submitted to the ESIS Environmental Health Laboratory, an AIHA accredited laboratory, where they were solvent desorbed and analyzed by gas chromatography using an NPD detector. Air samples collected in the BASF Houston Research and Training Center during the trimming of aged SPF were obtained in accordance with the procedure described in the draft ASTM work item 40292 “Sampling and Determination of Vapor-Phase Organic Compounds Emitted from SPF Insulation in Micro-Scale Chambers using Sorbent Tubes Analyzed by Thermal Desorption Gas Chromatography and Mass Spectrometry”. MSA Escort pumps equipped with Flow Gemini low flow adapters were used to draw air through glass tubes containing Tenax® sorbent material. Following sample collection, both amine catalyst and TCPP were thermally desorbed from the Tenax® and analyzed by the GC/MS method described in the draft ASTM standard. Acetaldehyde and Formaldehyde

The pumps were calibrated to a flowrate of around 1 liter/min. The average flowrate was used to calculate air volumes unless otherwise noted. Samples were collected on glass tubes containing silica gel coated with 2,4-dinitrophenylhydrazine per NIOSH Method 2016. The glass tubes containing silica gel coated with 2,4-dinitrophenylhydrazine, along with a blank tube, were shipped to the BASF lab in Wyandotte, Michigan. The samples were analyzed following NIOSH 2016 Method at an AIHA accredited laboratory. The concentration of aldehydes and formaldehyde were reported as >ppm. Total Volatile Organic Hydrocarbon (TVOC) EPA Method TO-15 The atmosphere sample is drawn into a specially-prepared stainless steel canister. The canister is an evacuated canister that is cleaned of all residual chemicals and sealed. A field sample of air is drawn through an orifice connected to the can. A gauge to regulate the rate and duration of sampling into the pre-evacuated canister that is selected for use. Canisters were sealed and shipped back to a third party laboratory for analysis per EPA TO-15 method for the first and second homes. It should be noted in the laboratory report, ppb concentrations of acetone, hexane, ethanol and toluene were detected which are not reported in this paper. These were all expected due to construction of the homes. Toluene was introduced to each home by the toluene impinger method used to capture MDI. Thus, these chemicals were not reported herein. As a result of the data collected in the previous study, TVOC samples were not collected in the open spraying of the warehouse.


SAMPLE LOCATIONS Laboratory evaluation – Trimming of foam

I

In an effort to evaluate emissions under controlled conditions, air monitoring and personal samples were completed at BASF’s Research and Training Center in Houston. Buns, approximately 2ft x 2ft were sprayed with the open cell formulation and placed in a ventilated spray booth. The mechanical ventilation was not in operation throughout the experiments to simulate worst-case scenario. Air monitoring and personal samples were then conducted during a 30 minute period as the panels were cut and scraped. Both foam sprayed 5 days previously (aged foam) and foam sprayed 4 hours prior to sampling (fresh foam) were tested. Area samples gathered, from aged and fresh foam, for MDI, were all below detection limits. Personal samples were obtained for the amine catalysts for both aged and fresh foam. Personal samples results for the amine catalysts N,N,N,-Trimethylaminoethylethanolamine or TMAEEA and N-[2-(dimethyl amino) ethoxy] ethyl]-N-methyl-1,3-propanediamine or DMAEEMPDA were below detection limits. Air monitoring samples of TCPP, from aged and fresh foam, detected extremely low values. See the below comparison of the before and after reformulation of the catalyst emissions.

Sample collection equipment is indicated by RED arrows in the photograph.

Mushroom like buns of foam mock ups were used, so continuous measurements could be taken while several buns were trimmed during the sampling time.


Field application of the new formulation in a large warehouse in Houston, Texas The field applications were performed by D7 Spray Foam Insulation employees who followed OSHA’s requirements for PPE and industry best practices. This included nitrile gloves, a full face air supplied respirator, full Tyvek® suit which there was no exposed skin. All individuals not spraying or helping, or wearing appropriate PPE during and immediately after application, were not allowed in the spray area. PPE was used by those monitoring near the spray area or in or near the house. The collection and work stations were located well away from the active spray or trimming areas. The new open cell formulation was applied to a large, open, warehouse in the suburban Houston area. MDI, TCPP and amine catalysts were monitored for at 15 and 30 feet from the SPF application. The sampling location was moved as the sprayer moved to keep these distances. • MDI - 2 area samples: 15 ft. from applicator (0.12 ppb), 30 ft. from applicator, (0.099 ppb) • TCPP - 2 area samples: 15 ft. from applicator (0.14 mg/m3), 30 ft. from applicator, (0.095 mg/m3). • Amines – The non-emissive replacement catalyst DMAEEMPDA and TMAEEA measured during application:

2 personal samples, sprayer and helper (both below detection limits): 15 ft. and 30 ft. from applicator non-detect


New Home in Houston, TX March 17-18, 2015 House area air monitoring set up


Field sampling of the new formulation occurred in mid-March of 2015 for evaluation of amine emissions and follow up of aldehydes. Aldehydes were sampled to ensure that they were not being generated from the SPF system. Background samples from the interior of the home and outside of the home were gathered. All reported results were in the ppb range (1 ppb) or below the detection limit. After not detecting MDI in previous air sampling work, after (0.5 – 1 hour) spraying, the author decided to discontinue sampling for MDI. The following day, aldehyde samples were gathered in the second floor theater room 10-15 ft. and 25-30 ft. from SPF application with results also in the ppb range (1 ppb) or below detection except for acetaldehyde at 17 ppb. Due to the many building products used, it was suspected that the aldehydes may have been from other trades in the area. TCPP samples were also gathered at these same locations. They ranged from 0.11 to 0.13 mg/m3. Amine catalysts (TMAEEA and DMAEEMPDA) personal samples were collected on the sprayer, the helper during spraying, and the trimmer after application. All concentrations were below the analytical detection limit of 8 micrograms (<0.06 to <0.09 ppm) for TMAEEA and 18 micrograms (<0.10 to <0.14 ppm) for DMAEEMPDA. As noted, applicators were in full PPE.

Houston Spray with helper OVERALL CONCLUSIONS Low Density High Pressure Open Cell Formulation – Houston Study Air samples collected during the high pressure application and trimming of low density SPF insulation (See similar papers on closed cell foam and open cell foam presented at the 2013 and 2014 Polyurethane Technical Conference, respectively) indicated mechanical ventilation may be required to reduce potential chemical exposures for sprayers, helpers, and trimmers. Although chemical emissions would be expected to be elevated for SPF applicators, the 2014 study (“Spray Polyurethane Foam Monitoring and Re-Occupancy of High Pressure Open Cell Applications to New Residential Constructions”) demonstrated that trimming open cell foam may also result in potential exposure for workers performing the work task due to emissive amine catalyst emissions. By substituting emissive catalysts with a non-emissive catalysts, catalyst emissions were significantly reduced during trimming activities. SPF applicators and helpers should continue to wear full face air supplied respirators, disposable chemical resistant clothing and gloves during application. It is also recommended that appropriate PPE and work practices recommended for SPF trimmers should be continued. If the trimmer is near the SPF applicator, then the trimmer must wear the same PPE as applicator. If the foam has cured and the SPF applicator is not applying foam, disposable clothing, gloves and a dust respirator is appropriate.


1Any technical advice furnished or recommendation made by the authors concerning any use or application of any product is believed to be reliable but the authors make no warranty, either express or implied, as to its accuracy or completeness or of the results to be obtained. With regard to any handling of any product, the end user assumes full responsibility for quality control, testing and determination of suitability of product for its intended application or use.

ACKNOWLEDGEMENTS

This study was conducted and supported by Bill Robert, Jim Andersen; Michael Sievers of BASF Corporation; Richard Wood of Air Products and Chemicals, Inc.

The project was completed with the support of various BASF Corporation employees including:

James Hannan, Todd Wishnewski, Spencer Davis, Lisa Vuong-Mun of BASF Corporation, Glen Perrin of D-7 Spray Foam Insulation

Industrial Hygiene & Environmental Analytics Lab

Elizabeth Hugel

William Robert, CIH

This paper may contain copyrighted material, the use of which has not always been specifically authorized by the copyright owner. In accordance with Title 17 U.S.C. Section 107, the material in this paper is being used for nonprofit educational purposes and will not be made available for distribution. ACC believes this constitutes a ‘fair use’ of any such copyrighted material as provided for in section 107 of the US Copyright Law. For more information, go to:http://www.copyright.gov/title17/92chap1.html#107. If copyrighted material from this paper is further used for purposes that go beyond “fair use,” permission from the copyright owner must be obtained.

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Open Cell Monitoring, a Follow-up After Reformulation · In this follow up study, after reformulation of the catalyst package, the half-pound open cell SPF formulation, was applied