From: "Cassidy Mike" <MICHAEL.CASSIDY@kohler.com>

Sent: 05/28/2009 12:36 PM

To: Jeff Telander/RTP/USEPA/US@EPA 

Cc:

Subject: RE: Emission Test Data for Kohler Company

Jeff,

Some of the follow-up items from our discussion last Friday (May 22) are:

1) Alternatives and options for glaze spray booth emission limitations

2) Options for if and how shuttle kilns (periodic kilns) should be addressed

3) Options for if and how refire (2-fire) kilns should be addressed

This e-mail presents some thoughts I have on item 1) above.

Sanitaryware glaze spraying is a coating operation that applies an aqueous ceramic glaze onto 

sanitaryware clay bodies prior to the ware being fired in kilns. While all three of Kohler Co.'s 

sanitaryware manufacturing facilities are not major sources individually, each is co-located with a 

separate and distinct major source, and so each sanitaryware facility has its own Title V air permit. 

These operating permits require the use of overspray control devices (water curtains, dry filters, etc.) at 

each glaze spray station and require documentation that each control device is operating properly in 

order for glaze to be sprayed.

For the Clay MACT, 'HAP-free' glazes and glaze spray operations should be excluded from any emission 

limitations that may be developed.

'HAP-free' can be justifiably defined as a HAP content less than 0.1% by weight (dry basis) HAP. This 

threshold is consistent with other EPA rule requirements. HAP-free glazes can be determined in two 

ways: 1) by each individual glaze color being <0.1% HAP, or 2) by the average HAP content of all glaze 

colors being <0.1% HAP on a weighted basis based on actual use of each color.

This averaging approach is consistent with several other MACT standards that apply to surfacing coating 

applications. Some examples are below.

Subpart MMMM, Surface Coating of Miscellaneous Metal Parts and Products: This MACT applies to 

sources that use 250 gallons per year or more of coatings that contain HAP. If a source exceeds this 

threshold use for HAP-containing coatings, then the emission limitations (lb HAP/gallon coating solids) 

by coating type in the MACT must be met. The emission limitations can be met by: 1) each individual 

coating must meet the limit, or 2) the average of all coatings must meet the limitation. Approach 2) lets 

sources use some low use coatings that may exceed the HAP limitation in the MACT by averaging this 

use with higher use coatings that are no HAP or low HAP.

Subpart PPPP, Surface Coating of Plastic Parts and Products: This MACT applies to sources that use 100 

gallons per year or more of coatings that contain HAP. If a source exceeds this threshold use for HAPcontaining coatings, then the emission limitations (lb HAP/gallon coating solids) by coating type in the 

MACT must be met. The emission limitations can be met by: 1) each individual coating must meet the 

limit, or 2) the average of all coatings must meet the limitation. Approach 2) lets sources use some low 

use coatings that may exceed the HAP limitation in the MACT by averaging this use with higher use 

coatings that are no HAP or low HAP.
Subpart WWWW, Reinforced Plastics Composites Production: This MACT sets emission limitations 

(emission factors in lb HAP/ton material) based on type of material applied and the type of operation. 

The emission limitations can be met by: 1) each individual coating and application type must meet the 

limit, or 2) the average for each combination of material and operation types must meet the limitation, 

or 3) the weighted average (by usage) of all material and application types must meet the limitation. 

Approaches 2) and 3) let sources use some low use materials that may exceed the HAP limitation in the 

MACT by averaging this use with higher use materials that are below the limitations.

As shown above, MACTs also incorporate material use thresholds for applicability. While I have no idea 

how the thresholds above were agreed upon, I believe the thresholds (250 gals/yr (Subpart MMMM) 

and 100 gals/year (Subpart PPPP)) are not higher because they address organic volatile HAPs, which do 

not become part of the coating and are emitted no matter how they are applied. This is not the case for 

aqueous ceramic glazes. The HAP contained in a ceramic glaze is part of the solids content of the glaze

and becomes part of the coating after it's applied. For this reason, it may be appropriate to set a higher 

threshold in the Clay MACT as potential HAP emissions from glaze application are far less for an 

equivalent amount of volatile organic HAP coating.

I think an appropriate threshold to consider for the Clay MACT would be 10,000 lbs/yr of HAP 

components used in all glazes. At this threshold, given transfer efficiency and overspray control 

efficiency, potential HAP emissions would be less than 1 lb/day. Considering that this <1 lb HAP/day 

could be emitted from several different spray booths/application stations, it is cost ineffective to require 

additional controls on these very low emitting sources.

For sources that exceed this threshold (use > 10,000 lbs HAP materials in all glazes), a HAP limitation 

could be expressed in terms of weight % (equivalent to lb HAP/lb coating solids - dry basis), or lbs 

HAP/gallon coating solids. This seems to be a more appropriate approach than a PM concentration 

approach in a spray booth exhaust stack.

I look forward to hearing your thoughts on the ideas expressed above for this topic, and I will send 

additional emails on items 2) and 3) above as I give some thought on how to approach them. Thanks, 

and let me know if any questions.

Michael J. Cassidy

EHS Specialist

Kohler Co.

444 Highland Drive

Mail Stop 009

Kohler, WI 53044

p. (920) 457-4441, x 77263

f. (920) 208-4744

mike.cassidy@kohler.com

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