Conditional Test Method 036

METHOD FOR MEASUREMENT OF TOLUENE DIISOCYANATE (TDI) AND METHYLENEDIPHENYL

DIISOCYANATE (MDI) STACK EMISSIONS
NOTE: This method is not inclusive with respect to specifications (e.g., equipment and supplies)
and sampling procedures essential to its performance. Some material is incorporated by
reference from other EPA methods. Therefore, to obtain reliable results, persons using
this method should have a thorough knowledge of at least the following additional test
methods found in 40 CFR Part 60: Method 1, Method 2, Method 3, and Method 4.
1.0 Scope and Application.
1.1 This method is applicable to the collection of Toluene Diisocyanate (TDI) and
Methylenediphenyl Diisocyanate (MDI) from the emissions associated with manufacturing
processes.
Examples of
Detection Limits Manufacturing
3 a
Compound Name CAS No. (µg/M ) Processes
2,4-Toluene
584-84-9 0.010 Flexible Foam
Diisocyanate (TDI)
2,6-Toluene
91-08-7 0.035 Flexible Foam
Diisocyanate (TDI)
2,4’-Methylenediphenyl
5873-54-1 0.636 Oriented Strand Board
Diisocyanate
4,4’-Methylenediphenyl
101-68-8 0.635 Oriented Strand Board
Diisocyanate
a 3
Estimated method detection limit is based on a sample volume of 0.25 M and a 5 mL sample
extraction volume.
2.0 Summary of Method.
2.1 Gaseous and/or aerosolized isocyanates are withdrawn from an emission source at an
isokinetic sampling rate and are collected on a 90 mm glass fiber filter coated with 10-12
2
µg/mm of 1-(2-pyridyl)piperazine (1,2-PP) or 1-(2-methoxyphenyl)piperazine (1,2-MP).
The primary components of the train include a filter cassette, and a sampling pump.
2.2 The collected samples are analyzed by high performance liquid chromatography (HPLC).
2.3 A correction factor of 1.19 was determined for each TDI isomer during Method 301
validation using 1,2-PP (3 replicates are required) and 1.1 for the 2,4-TDI isomer using
1,2-MP (6 replicates are required).
2.4 No correction factor is required for MDI using 1,2-PP.
3.0 Definitions. Not Applicable.
4.0 Interferences.
4.1 The greatest potential for interference comes from an impurity in the derivatizing reagent,
1-(2-pyridyl)piperazine (1,2-PP). 1-(2-Methoxyphenyl)piperazine (1,2-MP or MOPP) may
reduce or eliminate these interferences.
4.2 Other interferences that could result in positive or negative bias are (1) alcohols that could
compete with the derivatizing reagent for reaction with an isocyanate and (2) other
compounds that may co-elute with one or more of the derivatized isocyanates.

5.0 Safety.

TDI/MDI Emissions Procedure

Page 1 of 8
 5.1 The toxicity of each reagent has been precisely defined. The exposure to these
chemicals must be reduced to the lowest possible level by whatever means available.
The laboratory is responsible for maintaining a current awareness file of Occupational
Safety and Health Administration (OSHA) regulations regarding safe handling of the
chemicals specified in this method. A reference file of material safety data sheets should
also be made available to all personnel involved in the chemical analysis. Additional
references to laboratory safety are available.
6.0 Equipment and Supplies.
6.1 Sample Collection. The sampling train consists of the components detailed below.
Probe Nozzle. Approximately 8-12 inches x 0.125 inch ID Teflon® tubing sealed in a
stainless steel tube with a 90° bend. A glass or similar type probe may also be used. The
actual length and ID of the probe are dictated by the stack diameter and the ACFM.
Pitot tube. Type S, as described in Section 2.1 of promulgated EPA Method 2 (Section
6.1 of Reformatted Draft EPA Method 2), or other appropriate devices (see Vollaro, 1976
in Section 15.0, References). The Type S pitot tube assembly shall have a known
coefficient, determined as outlined in Section 4.0 of promulgated EPA Method 2 (Section
10.0 of Reformatted Draft EPA Method 2).
Pumping System. Gilian AirCon-2 air sampling pump or equivalent. Calibrate the pumps
with a Gilian Gilibrator-2 calibrator or equivalent.
Barometer. Mercury, aneroid, or other barometer capable of measuring atmospheric
pressure to within 2.5 mm Hg (0.1 in. Hg). In many cases the barometric reading may be
obtained from a nearby National Weather Service station, in which case the station value
(which is the absolute barometric pressure) is requested and an adjustment for elevation
differences between the weather station and sampling point is applied at a rate of minus
2.5 mm Hg (0.1 in. Hg) per 30-M (100 ft) elevation increase (vice versa for elevation
decrease).
Gas density determination equipment. Temperature sensor and pressure gauge (as
described in Sections 2.3 and 2.4 of promulgated EPA Method 2 (Sections 6.3 and 6.4 of
Reformatted Draft EPA Method 2)), and gas analyzer, if necessary (as described in EPA
Method 3). This determination is necessary only if the effluent stream is other than
normal room air.
Calibration/Field-Preparation Record. A permanently bound laboratory notebook, in which
duplicate copies of data may be made as they are being recorded, is required for
documenting and recording calibrations and preparation procedures. Electronic
notebooks may be used provided backups are preformed regularly, i.e., after each run
minimum.
6.2 Sample Recovery. The following items are required for sample recovery:
Glass Sample Storage Containers. Chemically resistant, borosilicate amber glass bottles,
20-mL VOA vials or 1 ounce. Bottles should be tinted to inhibit UV degradation. Screw-
cap liners shall be either Teflon® or constructed to be leak-free and resistant to chemical
attack by organic recovery solvents. Narrow-mouth glass bottles have been found to
exhibit fewer tendencies toward leakage.
Forceps. To handle filters before and after collection.

TDI/MDI Emissions Procedure

Page 2 of 8
7.0 Reagents and Standards.
7.1 Filter Preparation
7.1.1 Weigh 1.2g of 1-(2-pyridyl)piperazine (1,2-PP) or 1.4g of 1-(2-
methoxyphenyl)piperazine (1,2-MP) in a 50 mL volumetric flask, and dilute to the
mark with acetone. Mix well.
7.1.2 Transfer the solution to a Petri dish. Immerse 90-mm glass-fiber filters (Gelman
Sciences No. 61664 Type A/E Glass Fiber Filter or equivalent), one at a time for
20-30 seconds in the solution and place the filters on a nickel wire gauze to air
dry (complete drying takes several hours). Minimize exposure to light during
drying. Alternatively, a number of filters (up to 12) can be placed in the coating
solution and gently shaken to thoroughly wet all the filters (about 5 minutes). The
filters are then air dried individually on a nickel wire gauze.
7.1.3 Store the dry, coated filters in a cool, dark place until use.
7.2 Sample Recovery Reagents.
7.2.1 Dimethyl Sulfoxide (DMSO). Distilled-in-glass grade is required for sample
recovery and cleanup (see NOTE to 7.2 below).
7.2.2 Acetone. Distilled-in-glass grade is required for preparation of filters.
7.2.3 Acetonitrile. Distilled-in-glass grade is required if used for sample recovery and
cleanup.
7.2.4 Toluene. Distilled-in-glass grade is required if used for sample recovery and
cleanup.
7.2.5 Acetonitrile/DMSO Solution: Prepare a quantity of 90:10 (v/v) of
acetonitrile/DMSO sample preparation solution to meet needs of the sampling
event. Store the prepared reagent in a dark bottle containing 4A Molecular
Sieves.
NOTE: Organic solvents from metal containers may have a high residue blank and should not be
used. Sometimes suppliers transfer solvents from metal to glass bottles; thus blanks
shall be run prior to field use and only solvents with a low blank value (<0.001%) shall be
used.
8.0 Sample Collection, Preservation, Storage and Transport.
8.1 Field personnel should be trained in and experienced with the test procedures in order to
obtain reliable results.
8.2 Preliminary Field Determinations.
8.2.1 Select the sampling site and determine the stack pressure and temperature using
EPA Method 2. It is recommended that a leak-check of the pitot lines (see
promulgated EPA Method 2, Section 3.1 (Reformatted Draft EPA Method 2,
Section 8.1)) be performed. Determine the stack gas moisture content using
EPA Approximation Method 4 or its alternatives to establish estimates of
isokinetic sampling-rate settings. Determine the stack-gas dry molecular weight,
as described in promulgated EPA Method 2, Section 3.6 (Reformatted Draft EPA
Method 2, Section 8.6). If integrated EPA Method 3 sampling is necessary for
molecular weight determination, i.e. if other then room air, the integrated bag
sample shall be taken simultaneously with, and for the same total length of time
as, the sample run.
8.2.2 Select a nozzle size based on stack velocity so that isokinetic sampling rates can
be achieved with the available pumps. For the AirCon-2, a typical rate is 9-15

TDI/MDI Emissions Procedure

Page 3 of 8
 L/min. During the run, do not change the nozzle.
8.2.3 A typical sample volume to be collected is 250 - 350 L. The sample volume can
be adjusted as necessitated by analytical detection limit constraints and/or
estimated stack concentrations. A maximum limit should be determined to avoid
exceeding the capacity of the reagent.
8.2.4 In some circumstances (e.g., batch cycles) it may be necessary to sample for
shorter times and to obtain smaller gas-sample volumes.
8.3 Preparation of Sampling Train.
8.3.1 During preparation and assembly of the sampling train(s), keep all openings
where contamination can occur covered with Teflon® film or aluminum foil until
just prior to assembly or until sampling is about to begin (see picture).
8.3.2 Monitor the gas entry temperature. Ensure proper gas entry temperature before
proceeding and again before any sampling is initiated. It is important that the gas
entry temperature not exceed approximately 100° C (212° F), thus minimizing the
loss of reagent from the filter.
8.3.3 Just prior to sample collection, the flow rate through the train is set to meet
isokinetic conditions using a Gilibrator-2 flow calibrator or prepare a calibration
curve plotting the rotameter setting versus the actual flow rate through the train
prior to the sampling event.
Sampling Train

8.4 Sampling-Train Operation.

8.4.1 During each of the three (3) sampling runs (or 6 runs in the case of 1,2-MP
reagent and TDI), maintain an isokinetic sampling rate.
8.4.2 For each run, record the data required on a data sheet such as the one shown in
Figure 1. Be sure to record the initial start time.
8.4.3 When the probe is in position, block off the openings around the probe and stack
access port to prevent unrepresentative dilution of the gas stream.
8.4.4 A single train shall be used for the entire sample run.
8.4.5 During the course of the sample collection, monitor the flow by observing the flow

TDI/MDI Emissions Procedure

Page 4 of 8
 meter to ensure that the desired flow rate is maintained.
8.4.6 At the end of the sample run, record the final time.
8.5 Sample Recovery.
8.5.1 Preparation.
8.5.2.1 Transfer the probe and the filter holder assembly to the cleanup area.
This area should be clean and protected from the weather to minimize
sample contamination or loss.
8.5.2.2 Transfer approximately 10 mL of 90:10 (v/v) acetonitrile/DMSO,
acetonitrile, or toluene directly from the reagent bottle being used and
place in a separate, pre-labeled glass sample container for use as a
reagent blank.
8.5.2.3 Inspect the train prior to and during disassembly and note any abnormal
conditions.
8.5.2 Sample Containers.
8.5.2.1 Separate the filter housing and place the filter in the container. Add 5.0
mL or 10.0 mL of 90:10 (v/v) acetonitrile/DMSO, acetonitrile, or toluene
directly to the vial containing the filter. The volume is based on expected
concentrations of the isocyanate. The vial is sealed and properly labeled.
8.5.2.2 Place an unexposed filter in a container and add 5.0 mL or 10.0 mL of
90:10 (v/v) acetonitrile/DMSO, acetonitrile, or toluene directly to the
container containing the filter. The container is sealed and labeled as the
Field or Media Blank.
8.5.2.3 Sample Preparation for Shipment. Prior to shipment, recheck all sample
containers to ensure that the caps are well secured. If necessary, seal
the lids with Teflon® tape. Ship all samples upright, using the proper
shipping materials as prescribed for hazardous materials.
9.0 Quality Control.
9.1 Sampling.
9.1.1 Field or Media Blanks. Field or media blanks must be submitted with the samples
collected at each sampling site. The field or media blanks include the sample
bottles containing aliquots of sample recovery solvents, and unexposed filters
processed as a normal sample.
9.1.2 Reagent Blanks. A 10 mL aliquot, of 90:10 (v/v) acetonitrile/DMSO, acetonitrile,
or toluene, and the reagent solution used to prepare the filters must be included
in the analytical scheme.
10.0 Calibration and Standardization.
NOTE: Maintain a laboratory log of all calibrations.
10.1 Probe Nozzle. Probe nozzles shall be calibrated before their initial use in the field. Using
a micrometer, measure the inside diameter of the nozzle to the nearest 0.025 mm (0.001
in.). Make measurements at three separate places across the diameter and obtain the
average of the measurements. The difference between the high and low numbers shall
not exceed 0.1 mm (0.004 in.).
10.2 Pitot Tube Assembly. The Type S pitot tube assembly shall be calibrated according to the
procedure outlined in Section 4 of promulgated EPA Method 2 (Section 10.1, Reformatted
Draft EPA Method 2), or assigned a nominal coefficient of 0.84-0.85 if it is not visibly

TDI/MDI Emissions Procedure

Page 5 of 8
 nicked, dented, or corroded and if it meets design and intercomponent spacing
specifications.
10.3 Sampling System.
10.3.1 Before its initial use in the field, the pumping system shall be calibrated using a
Gilian calibrator or equivalent.
11.0 Procedures.
11.1 Sampling Operation. Follow the sampling procedure outlined in Section 8.5.
11.2 Analytical. See Reference 15.2 for typical HPLC conditions.
12.0 Method Performance.
12.1 Method Performance Evaluation. Evaluation of analytical procedures for a selected series
of compounds must include the sample-preparation procedures and each associated
analytical determination. The analytical procedures should be challenged by the test
compounds spiked at appropriate levels and carried through the procedures.
12.2 Method Detection Limit. The overall method detection limits (lower and upper) must be
determined on a compound-by-compound basis because different compounds may
exhibit different collection, retention, and extraction efficiencies as well as the
instrumental minimum detection limit (IDL, See Table). The method detection limit (MDL)
must be quoted relative to a given sample volume. The upper limits for the method must
be determined relative to compound retention volumes (breakthrough). Method Detection
Limits may vary due to matrix effects and instrument conditions.
Table 1 Instrument Detection Limits
Compound Instrument Detection Limit SD
2,4-Toluene diisocyanate 0.0010 ng/µL 0.0009
2,6-Toluene diisocyanate 0.0017 ng/µL 0.0016
2,4’-Methylenediphenyl
0.03178 ng/µL 0.0233
diisocyanate
4,4’-Methylenediphenyl
0.03175 ng/µL 0.0233
diisocyanate

12.3 Method Precision and Bias. The method bias is dependent upon the collection, retention,
and extraction efficiency of the train components. Evaluation data show that a correction
factor of 1.19 is required for both the 2,4- and 2,6-TDI isomers when using 1,2-PP
reagent and 3 replicates must be obtained. No correction factor is required for the 2,6-
TDI isomer when using 1,2-MP and a 1.10 correction factor is required for the 2,4-TDI
isomer when using 1,2-MP and 6 replicates must be obtained. No correction factor is
required for MDI when 1,2-PP is used.
13.0 Pollution Prevention. Not Applicable.
14.0 Waste Management. Not Applicable.

TDI/MDI Emissions Procedure

Page 6 of 8
15.0 References.
15.1 U.S. Environmental Protection Agency, 40 CFR Part 60, Appendix A, Methods 1-4.
15.2 OSHA Method 47, Revised March, 1989, Carcinogen and Pesticide Branch, OSHA
Analytical Laboratory, Salt Lake City, Utah.
15.3 Bayer Corporate Industrial Hygiene Laboratory, Bayer CIHL Method No: 1.7.7.
16.0 Tables, Diagrams, Flowcharts, and Validation Data. Not Applicable.

TDI/MDI Emissions Procedure

Page 7 of 8
Field Sampling Log

Site Name: Stack size:

Location: Velocity:
Date: Nozzle size:

Sampling
Pump Volume
Sample Period Total
Flow Sampled
Number Start End Time
Rate Liters
Time Time Stack Location Pump Number

Comments:

Figure 1. Field Data Sheet.

TDI/MDI Emissions Procedure

Page 8 of 8