Date: September 2, 2008 

 (Finalized: December 8, 2008) 

Subject: Site Visit – Lawrenceville Brick, Inc. Lawrenceville, Virginia 

Brick and Structural Clay Products Manufacturing NESHAP 

EPA Contract No. EP-D-06-118; EPA Work Assignment No. 2-09 

RTI Project No. 0210426.002.009 

From: Richard Marinshaw 

 Tom Holloway 

Gabrielle Raymond 

To: Jeff Telander 

EPA/SPPD/MMG (D243-02) 

U. S. Environmental Protection Agency 

Research Triangle Park, N.C. 27711 

I. Purpose 

The purpose of this visit was to observe the brick manufacturing process at the 

Lawrenceville Brick, Inc. (Lawrenceville) facility and to collect information on sources of 

hazardous air pollutant (HAP) emissions and emission controls in support of the redevelopment 

of national emission standards for hazardous air pollutants (NESHAP) for the brick and 

structural clay products industry. 

II. Place and Date 

Lawrenceville Brick, Inc. 

16024 Governor Harrison Parkway 

Lawrenceville, Virginia 23868 

July 30, 2008 

III. Attendees 

Lawrenceville Brick 

 

Leon Williams, Senior Vice President-Production 

Telephone: (434) 848-3151 

Bill Parrish, Safety and Environmental Manager 

Sam Lewis, Plant Manager, Plant 3 
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Darren Talbert, Plant Manager, Plant 4 

The Brick Industry Association (BIA) 

Terry Schimmel, Boral Bricks, BIA MACT Task Force Lead 

Telephone: (334) 480-2488 

U. S. Environmental Protection Agency 

Jeff Telander 

Telephone: (919) 541-5427 

RTI International 

Tom Holloway 

Telephone: (919) 316-3733 

 

Richard Marinshaw 

Telephone: (919) 316-3735 

Gabrielle Raymond 

Telephone: (919) 541-7015 

IV. Discussion 

A. Background 

The Lawrenceville Brick, Inc. facility, located in Lawrenceville, Virginia, manufactures 

several products, including face brick, building brick, pavers, structural brick, and other shapes. 

The Lawrenceville facility consists of two plants: Plant 3 and Plant 4. Plant 3 includes a natural 

gas-fired tunnel kiln that has a production capacity of 129,648 tons per year (ton/yr) of fired 

brick. Plant 3 has been operating since the 1990’s. Plant 4 includes a similar-sized natural gasfired tunnel kiln with a production capacity of 129,648 ton/yr of fired brick. Plant 4 was built in 

2003. Both plants are currently operating at about 60 percent capacity. 

The facility operates 24 hours per day, 7 days per week; brick forming and firing 

operations operate continuously, while the mining and raw material operations operate 5 days per 

week, or as needed depending on the production schedule. Lawrenceville employs up to 

140 employees at the facility. 

B. Process 

Lawrenceville manufactures structural bricks in both plants, and the same basic process is 

used for producing bricks at each of the plants. The primary difference between the two plants is 

the degree of automation; in Plant 4, much more of the equipment is automated than in Plant 3. 

The process steps include raw material storage, crushing, screening, grinding, mixing, forming, 

drying, and firing. The following paragraphs describe structural brick production in more detail. 

Attached is the non-confidential handout provided by the BIA at the start of the site visit. 
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Lawrenceville uses a combination of 40 percent shale and 60 percent clay to manufacture 

bricks. The shale used by Lawrenceville is actually a type of hard schist. As a result, clay is 

added to provide enough plasticity to the mixture for shaping. In addition, the green brick must 

be fired at a higher temperature than is typical for a Triassic shale. The raw materials are mined 

at two different locations, each of which is about 15 minutes away from the facility. Each mine 

has about a year’s worth of material stockpiled. The raw materials are trucked to the facility 

where a 3-week supply of shale and a 1-month supply of clay are maintained in covered storage. 

The following paragraphs describe the operations performed in the two plants. Plant 3 is 

described first, followed by the description of Plant 4. 

1. Plant 3. The raw material is first transferred to a primary crusher, which reduces 

the material size from up to 18 inches to about 4 inches. The crusher has a capacity of 

approximately 300 tons per hour (ton/hr). The material is transported by conveyor to the 

grinding room. In the grinding room, the material is fed to a series of screens, where oversize 

material is transferred to a hammermill, and undersize material is transferred to finishing screens. 

The hammermill has an operating capacity of 275 ton/hr. The ground material is transported by 

conveyor and front end loader to the forming area. Here, the moisture content, typically about 

13 percent, is measured, and body additives and colorants, such as soda ash, manganese dioxide, 

and iron oxides, are added. The material is fed into a pug mill, where the raw material is mixed 

with water to raise the moisture content to about 18 percent. The material is vacuum-extruded 

from the pug mill as a continuous column onto an open conveyor belt. Liquid and powder can 

be added on top of the column to add color to the bricks. The column may also pass through a 

roller to add texture to the bricks. The next step is cutting. The column is cut into slugs, and 

then cut by wire into 30 individual “green” bricks. The green bricks travel by conveyor to the 

setting machine, where they are automatically set on the kiln cars. Netting is wrapped around the 

stacks of brick to provide more stability to the stacks during drying and firing. Another option 

for the green bricks is to be cut again manually to create unique shapes. This is only for special 

orders. 

The kiln cars loaded with green bricks are next rolled down a track to the dryers. Drying 

typically takes about 2 days and is complete when the bricks have reached a moisture content of 

1 percent. The dryers are heated with waste heat from the cooling zones of the kilns. The kiln 

cars then are mechanically rolled out of the dryers and into the tunnel kiln, where they are fired. 

After drying, the kiln cars loaded with the dried brick are pushed through the kiln 

according to a set schedule. The temperature within the kilns varies along the length of the kiln. 

From the entrance, the temperatures within the kiln are ramped up to a maximum in the firing 

zone, which is maintained around 2030F. After the firing zone, the kiln temperature decreases 

gradually until the bricks enter the cooling zone of the kiln. After cooling, the cars exit the kiln 

and are rolled outside the kiln to an unloading area. There, the bricks are manually unloaded 

from kiln cars, packaged, and transported to an open storage area outside the covered plant.

2. Plant 4. The process used in this plant is similar to the brick manufacturing 

process that is used in Plant 3. However, Plant 4 is largely automated, so most of the manual 

operations that are performed in Plant 3 are performed robotically in Plant 4. The raw material 

crusher, grinder, and screens have similar capacities to the equipment in Plant 3. However, after 
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grinding in Plant 4, the material is stored in a series of zones in the reclaim building. An 

automated reclaimer withdraws the material from storage and transfers it to a conveyor, which 

then transports it to the brick forming area. The forming, drying, firing, and packaging steps of 

the process are similar to those described above for Plant 3. 

C. Emissions and Controls 

The primary emission units are the kilns. Emissions from the tunnel kiln in Plant 3 are 

controlled with a dry limestone adsorber (DLA), which was retrofitted in 2006. Emissions from 

the tunnel kiln in Plant 4 are controlled with a dry injection fabric filter (DIFF), which was 

installed with the kiln in 2003. Lawrenceville decided to install a DIFF instead of a DLA on the 

Plant 4 kiln to ensure the kiln could meet the proposed emission limit for hydrochloric acid 

(HCl). However, the final rule specified a less stringent HCl emission limit, which the plant 

could meet using a DLA. Although both the DLA and DIFF were installed to comply with the 

original NESHAP, the facility is now classified as a synthetic minor source. The operation of the 

DLA and DIFF is described in the following paragraphs. 

In the DLA, limestone is fed into a reaction chamber at the top of the unit at a rate of 

157 pounds per hour (lb/hr). The limestone cascades through multiple baffles within the 

chamber and reacts with the exhaust gases from the kiln, which flow across the reaction 

chamber. When the limestone reaches the bottom of the chamber it is transferred by augur to a 

descaler, which is equipped with serrated blades to remove the reacted material on the surface of 

the limestone. The processed limestone is then conveyed pneumatically back to the top of the 

reaction chamber. New limestone is periodically added to the system as needed, as reacted 

limestone is removed. Lawrenceville obtained approval from the State for alternative monitoring 

of the DLA operation. Rather than monitor pressure drop across the DLA, the plant must 

monitor the bypass damper position. In addition, the plant uses level indicators to monitor and 

ensure there is adequate limestone in the feed hopper. 

In the DIFF, the exhaust gases enter a reaction chamber, where hydrated lime is fed at a 

rate of 89 lb/hr. The exhaust gases then are pulled through a pulse-jet fabric filter, where 

reaction products and other particulate matter are removed from the exhaust stream. The lime 

that is not carried by the exhaust gas stream into the fabric filter is collected in a hopper and 

recirculated through the system. Fresh reagent is added at a ratio of 10:1 (recirculated to fresh 

reagent). The fabric filter includes 768 bags made of polytetrafluoroethylene (PTFE), which 

have a maximum operating temperature of 500°F. Lawrenceville has not determined the average 

lifetime of the filter bags, but noted that a full set of bags for the DIFF costs approximately 

$150,000. 

Waste material from the DLA and DIFF is shipped off-site for agricultural applications. 

In addition, Lawrenceville is currently working with Virginia Tech to develop options for selling 

the waste material as a soil amendment. 

Plant personnel pointed out that the costs to install and operate the DIFF at Lawrenceville 

have been significantly higher than the costs to install and operate the DLA. The installed cost 

for the DLA was approximately $900,000, and the installed cost for the DIFF is about 

$1,300,000 in today’s dollars. The annual operating costs for the DIFF are about $150,000 more 
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than the costs to operate the DLA. One difference in operating costs results from the need to 

replace fabric filter bags periodically, which is estimated to be about $50,000 per year on 

average for replacements. Another difference in operating costs results from the larger exhaust 

fan motor in the DIFF. After an 18% increase by Virginia Dominion Power, the electrical costs 

for the DIFF are now about $60,000 more per year than for the DLA. The remainder of the 

additional costs is mainly for the higher costs of the hydrated lime versus the pellet lime used in 

the DLA. Labor costs for normal operation are not included in this analysis. In addition, the 

exhaust into the DIFF must be maintained at a temperature high enough to preclude acid gases 

from condensing within the fabric filter and destroying the bags. To ensure adequate inlet 

temperatures, the system is equipped with an auxiliary burner to heat the inlet air when 

necessary. Lawrenceville continuously monitors the pressure drop across the fabric filter, and 

filter bag cleaning is triggered when the pressure drop exceeds the set point for the system. 

Stack tests on the two kilns indicated the DIFF-controlled kiln has HF emissions of about 

0.45 ton/yr, and the DLA-controlled kiln emits about 0.65 ton/yr of HF. Uncontrolled HF 

emissions from each of the kilns are about 22 to 25 ton/yr.