Some manufacturers, such as General Shale Products LLC in Johnson City, Tenn., are capitalizing on the growing popularity of structural brick in the U.S. According to Jim Bryja, structural brick has several advantages over other building materials. There are no internal walls, so the interior space of a building is more flexible. Additionally, there are no interruptions of mechanical or electrical piping, making the building effective for insulation. A 45⁄8 in. bed depth is the company’s most popular structural brick for residential or smaller scaled commercial applications because of its appearance, Bryja said. Structural brick is also gaining popularity in low-rise commercial construction building. The brick can be left to serve as both the internal and external walls—no interior finish is required.
One of the major problems for the brick industry is the time required for a traditional mortar-based bricklaying operation and the lack of skilled laborers. Alternative bricklaying methods may be needed to ensure that brick remains a viable building material well into the future. Ceric Inc. in Denver, Colo., has been testing the feasibility of an interlocking brick wall system using experimental bricks made at Richtex. According to Christophe Aubertot, the interlocking system greatly reduces the need for mortar while maintaining a traditional jointed appearance. Using pumpable mortar, an average of 100 bricks per hour can be laid with an inexperienced crew.
According to Russell Brown, a graduate student at Clemson University in Clemson, S.C., U.S. brick manufacturers have developed a false sense of security because of the booming economy. Business is going so well that few see the need to develop new and innovative products. However, brick manufacturers should be using this time of prosperity to innovate so that they’ll have something to fall back on when times are lean, Brown said. The National Brick Research Center (NBRC) in Anderson, S.C., is assisting those efforts by testing components and characteristics such as anchor bolts, flexural strength, grout strength at early stages, and the use of “mortar soup”—slushed/souped-up mortar in lieu of grout. The NBRC recently acquired a one million pound compression-testing machine, and it has also embarked on a water-penetration study to determine the effects of surface texture on water absorption. Sophisticated software is being developed to analyze characteristics such as sound transmission, energy calculations and fire ratings and to help test veneers, pilasters, columns, multi-wythe walls and pre-stressed masonry. Another innovative idea that the NBRC might examine more closely in the future is the use of structural foam instead of grout. The point, Brown said, is to look beyond today so that brick will continue to meet builders’ needs well into the future.
New ASTM (American Society for Testing and Materials) standards may be required to more accurately evaluate the freeze/thaw durability of brick. According to Eric Seaverson from the NBRC, the majority of the current standards are based on a brick’s physical properties. However, preliminary findings from tests performed at the NBRC on seven brick types from six different manufacturers indicate that there is no correlation between freeze/thaw durability and a brick’s physical properties. A dilatometer, calipers and a comparator were used in the tests. The dilatometer provided the most accurate results, followed closely by the comparator. The calipers had a large margin for user error, Seaverson said.
When problems occur on brick in residential or commercial buildings, blame is usually assigned to the manufacturer first. But such problems are not always the manufacturer’s fault, said Jerry Carrier from Glen-Gery Corp., Shoemakersville, Pa. A commercial building using Glen-Gery’s brick was experiencing efflorescence on the brick face. After extensive testing, Glen-Gery discovered that the problem was a result of the cleaning solution being used. The brick was absorbing the cleaning solution and releasing it as efflorescence later on. Improper cleaning techniques were also part of the problem—the brick was not being kept wet enough to prevent it from absorbing any of the cleaning solution. More education is needed on the part of the consumer regarding how to clean brick.
Most MACT standards apply only to major sources of hazardous air pollutants, defined as facilities that have the potential to emit above 10 tons per year (TPY) HAPs, or 25 TPY sum of all HAPs. On March 23, 2000, the U.S. Environmental Protection Agency (EPA) presented a draft approach of the standards. The way the standards in this draft are written, about 100 tunnel kilns in the brick industry will require some form of control, as well as all new periodic kilns, Schimmel said. The anticipated required compliance date is between 2002 and 2005. A brick industry task force is currently trying to raise the tunnel kiln cutoff to reduce the number of kilns that would require controls; set more reasonable control efficiency levels that would allow manufacturers to use existing industry controls; remove the requirement for control on new periodic kilns; address issues for sawdust and coal-fired kilns; and ensure that monitoring, record keeping and reporting requirements are reasonable. No matter what the outcome, the federal MACT standards and other regulatory actions will impact the way brick manufacturers run their businesses, Schimmel said.
On the construction end of the equation, brick has the potential to become well known as an environmentally friendly building product. According to Denis Brosnan from the NBRC, data published about brick by the American Institute of Architects (AIA) in its Environmental Resource Guide (developed in cooperation with the U.S. EPA) is old and needs to be updated. Life cycle analysis tests done at the NBRC indicate that brick has a longer service life and more recycling potential than fiber cement and exterior insulation and finishing systems (EIFS) (synthetic stucco), two common building materials. However, EIFS still has a higher environmental rating because of the amount of fuel required to fire brick. Using hollow units and faster firing methods would reduce brick’s energy consumption to equal EIFS, Brosnan said.
Global Clay Marseilles in Marseilles, Ill., is undergoing a $14 million expansion, in which its production will increase from 66 to 136 million brick per year. Phase 1 of the project was brought online in early August 2000 and included the installation of a 496 ft Ceric sand seal kiln and a Proceram two-tunnel dryer, which holds 15 cars per tunnel. In October, the company was running at 172,000 brick per day and was preparing to install a Stedman 4260 Grand Slam impactor. A new dehacker and new packaging systems will also be installed to help handle the plant’s increased capacity.
Jenkins Brick in Montgomery, Ala., has been in the Jenkins family since 1986. According to Mike Jenkins V, record production at the time the family purchased the plant was 26 million brick. In 1999, the company produced 56 million brick, and by 2001 the company plans to produce 110 million brick. The company modified the plant to use landfill gas as an alternative fuel, and it also added a second Harrop kiln to handle the additional production. It currently operates with 74% landfill gas and also flashes its product using the landfill gas. The company has the ability in its kilns to blend the landfill gas with natural gas or run zone by zone. In 2001, the Montgomery plant plans to add a new grinding facility.
Fast firing is another technology that many brick plants are considering. In an invited presentation, Eckhard Rimpel from the Institut für Ziegelforschung Essen e.V. (Brick and Tile Research Institute), Essen, Germany, discussed the possibilities for and limitations of fast firing. For a successful fast firing operation, a manufacturer must have a low setting density, good air flow through the setting and single treatment of the bricks, Rimpel said. A test plant built at the Institut was used to evaluate different setting patterns. Brick were placed in a close block setting, a center gap setting, and a center gap/reduced roof gap setting. Researchers discovered that the heat transfer coefficient declined rapidly based on the setting pattern, with the center gap setting having the lowest heat transfer coefficient. A four-hour firing cycle from cold to cold is possible, but burners are needed in the preheat zone to ensure that the firing is complete. A side benefit to fast firing is that hazardous air pollutant (HAP) emissions can be reduced.
New hydrocasing kilns were recently installed in General Shale Products’ Moncure plants 24 and 25 in Moncure, N.C. The kiln cars run in water to achieve an efficient seal. According to Rod Schutt, the kiln uses much less power than a typical kiln, and the atmosphere can be tightly controlled.
According to Martyn Verster from Gerritse Systems Pannerden, Pannerden, The Netherlands, proper maintenance is necessary to extend the life of a plant’s kiln cars. Sweeping or vacuuming is labor-intensive and is not always effective. For this reason, automatic kiln car cleaning is becoming popular in Europe. Some cleaning systems feature gripper heads that lift the deck blocks, vacuum underneath them, then replace them. In some cases, such units can clean and center over two tracks. High-speed and high-capacity units are also available. But while they offer many benefits, the automated systems may not work for every plant. Any plant considering automatic systems must have the available floor space, available time for cleaning, and kiln cars and refractory layouts that can accommodate the gripper heads.
General Shale’s Knoxville, Tenn., plant replaced two old 384 grinders with a Grand Slam 4260 crusher/impactor from Stedman Corp. According to Andy Hall, the old grinders were costing the plant $27,000 annually for maintenance requirements, including replacement parts and lubrication oil. The new impactor has increased the amount of material going through the plant and requires an average of only $12,000 per year in replacement parts. The company also installed a pneumatic conveying system to control dust and facilitate plant cleanup. The system can be used to convey more than one type of sand without contamination, and also conveys the material to its destination much faster—10 seconds compared to 10 minutes in the previous system.
Y.J. Ahn explained how Richtex’s Plant 9 in Ninety-Six, S.C., doubled the output of its grinding department by installing a new Grand Slam impactor, scalping screens from Dyster and vibrating screens from Midwestern Industries. Installation of the new screens provided a 90 ton-per-hour material gain for both the company’s red and sox clay bodies. These improvements allowed the company to eliminate overtime hours and split shifts, and also reduced wear and tear on the company’s equipment.
Robots are increasingly being considered for all types of material and product handling applications. Today, one-armed robots are mass-produced and thus more affordable than they were several years ago, said Andreas Lingl from Hans Lingl GmbH & Co. KG, Neu-Ulm, Germany. Robots require much less maintenance because their parts are more durable, they are easily available, and they reduce the requirements for plant personnel. They are highly flexible and mobile and can carry out complex tasks, often replacing several conventional machines. However, these robots still have their limitations. Their cameras are only two-dimensional and do not have “depth;” therefore, their handling ability is only as good as the correct positioning of the product. Additionally, their carrying capacity is often limited, and overloading this capacity results in increased wear and tear on the equipment. Robots are not the best solutions for every application, Lingl said. For a plant that is merely moving product from one place to another, a gantry gripper might be a better, less expensive solution.
Designed by Gil Robinson, long-time professor of ceramic engineering, this course takes students on a hands-on journey from the clay pit through grinding and the mill room and with stops in drying and firing. The emphasis is on what happens and what controls each process. The characteristics of a good brick product are reviewed both from a standpoint of ASTM standards and from a standpoint of field experience. Defects and product problems are analyzed through practical examples.
The course devotes 50% of its time to hands-on testing of raw materials (particle size tests) and on green, dried and fired products from the student’s own plant. Experiments are practical, low cost and aimed at plant adaptation. The 50% of time spent on lecture features instruction by the NBRC staff and by industry professionals. The NBRC offers its own “Brickmaker Certification” for those passing a recreation of Robinson’s classic test at the end of the course.
For more information about this short course, contact Dr. Denis A. Brosnan, Program Chairman, P.O. Box 613, Pendleton, SC 29670; (864) 656-1094; fax (864) 656-1095; e-mail brick@Clemson.edu or visit www.brickandtile.org.