KISAN Bamboo Festival from 5 th June 2021 to 9 th June 2021

Brick sealer

Effect of MWR 1000 Water Repellent on Sponge

how to use a treated bamboo pole for structure? केमिकली ट्रीटेड बांबू क...

ट्रीटेड बांबू पासून बनविलेली नर्सरी Nursery shade from treated Bamboo poles

How to apply decking oil

Deking Oil

Pune Bamboo Festival 2020

Pune Bamboo Festival 2020 was organised jointly by Bamboo Society of India, Maharashtra chapter and Pune district Burud community.
This was first of this kind of event dedicated to bamboo only.
Pune Bamboo Festival On February 14, 15 and 16 was very exciting.
Organizers were shocked observing how much people love Bamboo.
The event was inaugurated by Maharashtra MLA Hon. Kishor Jorgewar.
Dr. Hemant Bedekar ,Executive Director ,Bamboo Society of India, Maharashtra Chapter elaborated bamboo as best substitute to wood and ecological and economical aspects of bamboo.
The inaugural ceremony was attended by Mr. V. Giriraj of Bamboo Promotion Foundation, Mr. Humnabadkar social activist, Dr. Nachiket Thakur prominent bamboo structures designer, Dr. Chitle of Savitribai Phule Pune University, Mr. Ajit Thakur,Bamboo researcher, Mr. Shrikrishna Kulkarni, bamboo treatment expert, Mr. Rajabhau Sapakal, Mr. Pramod Hadge, Mr. Pasalkar of Pasalkar timbers, Mr. Sonawane, Mrs. Sangeeta Kulkarni,Tissue culture consultant,Mrs. Medha Joshi, Architect Prarthana Mahakal, dignitaries of Burud community, Mr. Aashish Dole of Ashwini International, Mr. Misal of Bharat bamboo Cycles, Power generation expert from bamboo Mr. Arun Wandre,Mr. Ghubde a famous bamboo lover from Nagpur . Avanti Kalagram Arch. Deepak Bachal, Mr.Anand Patki, Mrs. Daya Patki Bamboo ornaments, Mrs. Bedekar, Dhanashree Bedekar, Abhijit Ganu Devrukh, Melghat Support Group, Burud Samaj Traders Association, Snehal Nursery Hinganghat, Mumbai Swastik Industries Mr. Sanjay and Mr. Durgesh ., Mr. Yogesh Shinde bamboo India, Mr. Dighe, Mr. Vishal from BANS Chandrapur. Mr. Kadam of Shloka Nursery, Mr.Navin Mali of Konbac, Kudal, Mr. Ajit Takke, Sayali Bamboo mats from Kolhapur, Ecobuddy, Bamboo structure specialist bamboo Life, Mr. Anantha of Aaksha Mangalore, Ginger Lime and thousands of Punekars were present.
Internationally well known bamboo expert Mr. Sanjeev Karpe elaborated his fascinating views on bamboo and its global consequences.
People from all over Maharashtra and other provinces showcased their products at the exhibition.
Particularly the amazing products of Surangana and tribal brothers attracted the attention of Pune.
In technical discussions, Dr. Bedekar, Dr.Nachiket, Mr. Ajit Thakur and Ashok Satpute guided the attendees.
Mr. Vinay Kolte gave very good guidance on bamboo cultivation.
Newspapers and television channels covered the event.
First citizen mayor of Pune Hon. Murlidhar Mohol, MLA Hon. Bhimrao Tapkir, Ex.MLA, Mr. Ramesh Dhamale, Vice Chancellor Mr. Karmalkekar, MLA Mr. Pasha Patel and thousands of dignitaries greeted the ceremony.
Mr. Vipul Kumthekar chemicals consultant, Ms. Shrushti Bhongale, Sanjay Kulkarni, Kaustubh and hundreds of activists actively participated in event.
Thanks to Mr. Samit Pawar, Mr. Niraj Mutha who is manufacturer of bamboo floorings from Agartala, Mr. Karpe for their support.
Thanks to all Bamboo-lovers from Pune and Maharashtra and neighbouring provinces.
Sorry if anyone has missed the mention

Our stall at CAP 2019 Mumbai 

2 Dec. 2019 to 4 Dec. 2019

Invitation to visit our stall X 66 at CAP 2019 Mumbai

Our stall at Korea Chem 2019

Range of wood treatment chemicals , construction chemicals, dyes and chemicals, summer cool paints ,rust and paint strippers and more

Mr. Ashish Dole at stall

Cordial invitation to visit our stall at Chemicals and plastics, Mumbai

How Termites make damages

How Termites make damages: 

Regardless of how your building is constructed or the type of foundation it has, termites can find a way in, concealing themselves from exposure by building special "shelter tubes." Because they work from the inside out, it's likely that you won't see signs of infestation until the damage is done 

Concrete slabs : 

Termites can infest the building through expansion joints where the floor adjoins the foundation around plumbing and electrical penetration, through cracks and the exterior surface of the slab or behind stucco and veneer coverings 

Basements: 

Termites can enter through voids in the foundation wall, expansion joints where the floor meets the wall. 

Conventional Foundation: 

Termites can invade your building through foundation voids, plumbing pipes and pier supports; on the surfaces of the foundation walls (exterior and interior); and through any wood-to-ground contacts. 

Disadvantages of traditional Chemicals

Disadvantages of traditional termite  chemicals: 

Artificial pesticides/chemicals can quickly find their way into food chains and water courses.

This creates health hazards for humans. There is also much concern for people. The products may be misused. 

Safety for the environment: 

There are a number of harmful effects that chemical pesticides can have on the environment.

Artificial pesticide can kill useful insects which eat pests. Just one spray can upset the balance between pests and the useful predators which eat them.

Artificial chemicals can stay in the environment and in the bodies of animals causing problems for many years.

Pests become resistant to pesticides so more powerful chemicals are needed. 

Many of traditional chemicals are considered as carcinogenic.

What is Termites

Termites are a group of insects consisting of 2,500 species of which 300 are considered pests. Termites are one of the most damaging pests in the tropics and can cause considerable problems in housing.

There are 2500 species of termites including subterranean termites, Thompson termites ,Termopsidae,  hodotermitidae, kalotermitidae, serritermitidae, etc. 

There are several families and sub-families. Some have nests underground, others in wood, for example hollow trees, and some build mounds. 

Termites are causing severe damages to buildings and constructions and structures all over the world and now a days it is a great problem to the industry.

Termites feed on cellulose, paper, plywood, cloths, bamboo, furniture, wood etc.Which are prone and very sensitive for termite attacks.

Besides  making tiny ways through the walls and structures, making the structure weak.

Termites enter through the foundation. Hence, it is most important to have preventive measures

Facts about Termites:

Live for 15 years and lay 1 egg every 15 seconds

Have 4 wings

Burrow tiny mud tunnels to a source of wood

Leave sawdust near windows

Enjoy wood resulting from leaky plumbing

Termites  might be in your home actually live 15-25 feet underground, and perhaps as far as 50 yards or more from your building.

Can destroy entire house in about 4-5 years in USA

A typical termite colony can number 300,000 to 3,000,000 workers.  Think in terms of a 200 ltrs drum full of squirming grains of rice… that’s a small colony.

Wood Fungi Solution

Pressure Treatment Process

Pressure treatment process

Courtesy  - Sheds   Direct

Wood Preservation study

Ref- Various sources

Wood is treated with preservatives to protect it from wood-destroying fungi and insects. Treating wood with preservative chemicals can increase the service life of wood by a factor of five times or more. Wood treated with commonly used wood preservatives can last 40 years or more in service. Preservative-treated wood (figure 1) is an economical, durable, and aesthetically pleasing building material and is a natural choice for many construction projects in the national forests. When treated wood is used in field settings, the possibility of environmental contamination raises concerns. There is increasing pressure to be environmentally friendly and to reduce, restrict, or eliminate the use of wood preservatives because of the concern that toxic constituents may leach from the treated wood. This report will provide an overview of preservative systems, help readers understand the level of risk and status of the science involved in evaluating preservative systems, and provide some guidelines for using the product .

Wood preservatives have been used for more than a century. They are broadly classified as either waterborne or oil-type, based on the chemical composition of the preservative and the carrier used during the treating process. Some preservatives can be formulated for use with either water or oil solvents. Water-based preservatives often include some type of cosolvent, such as amine or ammonia to keep one or more of the active ingredients in solution. Each solvent has advantages and disadvantages that depend on the application. Generally, wood preservatives also are classified or grouped by the type of application or exposure environment in which they are expected to provide long term protection. Some preservatives have sufficient leach resistance and broad spectrum efficacy to protect wood that is exposed directly to soil and water. These preservatives will also protect wood exposed aboveground, and may be used in those applications at lower retentions (concentrations in the wood)

Other preservatives have intermediate toxicity or leach resistance that allows them to protect wood fully exposed to the weather, but not in contact with the ground. Some preservatives lack the permanence or toxicity to withstand continued exposure to precipitation, but may be effective with occasional wetting. Finally, there are formulations that are so readily leachable that they can only withstand very occasional, superficial wetting. It is not possible to evaluate a preservative’s long term efficacy in all types of exposure environments and there is no set formula for predicting exactly how long a wood preservative will perform in a specific application. This is especially true for aboveground applications because preservatives are tested most extensively in ground contact. To compensate for this uncertainty, there is a tendency to be conservative in selecting a preservative for a particular application.

Oil-Type Preservatives

The most common oil-type preservatives are creosote, pentachlorophenol, and copper naphthenate. Occasion-ally, oxine copper and IPBC (3-iodo-2-propynyl butyl carbamate) also are used for aboveground applications. The conventional oil-type preservatives, such as creosote and pentachlorophenol solutions, have been confined largely to uses that do not involve frequent human contact. The exception is copper naphthenate, a preservative that was developed more recently and has been used less widely. Oil-type preservatives may be visually oily, or oily to the touch, and sometimes have a noticeable odor. However, the oil or solvent that is used as a carrier makes the wood less susceptible to cracks and checking. This type of preservative is suitable for treatment of glue-laminated stringers for bridges where cracks in the stringers could alter the bridges’ structural integrity

Creosote

 Coal-tar creosote is effective when used in ground contact, water contact, or aboveground. It is the oldest wood preservative still in commercial use in the United States. It is made by distilling coal tar that is created when coal is carbonized at high temperatures (1,652 to 2,192 degrees Fahrenheit [900 to 1,200 degrees Celsius]). Unlike other oil-type preservatives, creosote usually is not dissolved in oil, but it does look and feel oily. Creosote contains a chemically complex mixture of organic molecules, most of which are polycyclic aromatic hydrocarbons. The composition of creosote varies because it depends on how the creosote is distilled. However, the small differences in composition in modern creosotes do not affect their performance as wood preservatives. Creosote-treated wood is dark brown to black and has a distinct odor, which some people consider unpleasant. Creosote-treated wood is very difficult to paint. Workers sometimes object to creosote-treated wood because it soils their clothes and makes their skin sensitive to the sun. The treated wood sometimes has an oily surface. Patches of creosote sometimes accumulate, creating a hazard when it contacts the skin. Because of these concerns, creosote-treated wood often is not the first choice for applications such as bridge members or handrails, where there is a high probability of human contact. However, creosote-treated wood has advantages to offset concerns with its appearance and odor. It has a lengthy record of satisfactory use in a wide range of applications and is relatively inexpensive. Creosote is effective in protecting both hardwoods and softwoods and improving the dimensional stability of the treated wood. Creosote is listed in American Wood-Preservers’ Association (AWPA) Standards for a wide range of wood products created from many different species of trees. The minimum creosote retentions required by the standards are in the range of 5 to 8 pounds per cubic foot (80 to 128 kilograms per cubic meter) for aboveground applications, 10 pounds per cubic foot (160 kilograms per cubic meter) for wood used in ground contact, and 12 pounds per cubic foot (192 kilograms per cubic meter) for wood used in critical structural applications, such as highway construction. With heated solutions and lengthy pressure periods, creosote can penetrate wood that is fairly difficult to treat. Creosote is suitable for treatment of glue-laminated members. Creosote treatment does not accelerate, and may even inhibit, the corrosion of metal fasteners. Treatment facilities that use creosote are found throughout the United States, so this wood preservative is readily available. Creosote is classified as a Restricted Use Pesticide (RUP) by the U.S. Environmental Protection Agency (EPA). Producers of treated wood, in cooperation with the EPA, have created Consumer Information Sheets with guidance on appropriate handling and site precautions when using wood treated with creosote . These sheets should be available for all persons who handle creosote-treated wood.

Pentachlorophenol

Pentachlorophenol has been widely used as a pressure-treatment preservative in the United States since the 1940s. The active ingredients, chlorinated phenols, are crystalline solids that can be dissolved in different types of organic solvents. A performance of pentachlorophenol and the properties of the treated wood are influenced by the properties of the solvent. Pentachlorophenol is effective when used in ground contact, freshwater, or aboveground. It is not as effective when used in seawater. A heavy oil solvent (specified as Type A in AWPA Standard P9) is preferable when the treated wood is to be used in ground contact. Wood treated with lighter solvents may not be as durable. Wood treated with pentachlorophenol in heavy oil typically has a brown color, and may have a slightly oily surface that is difficult to paint. It also has some odor, which is associated with the solvent. Pentachlorophenol in heavy oil should not be used when frequent contact with skin is likely (handrails, for instance). Pentachlorophenol in heavy oil has long been a popular choice for treating utility poles, bridge timbers, glue-laminated beams, and foundation pilings. The effectiveness of pentachlorophenol is similar to that of creosote in protecting both hardwoods and softwoods, and pentachlorophenol often is thought to improve the dimensional stability of the treated wood. Pentachlorophenol is listed in the AWPA standards for a wide range of wood products and wood species. The minimum softwood retentions are 0.4 pounds per cubic foot (6.4 kilograms per cubic meter) for wood used aboveground, and 0.5 pounds per cubic foot (8 kilograms per cubic meter) for wood used in critical structural applications or in ground contact. With heated solutions and extended pressure periods, pentachlorophenol can penetrate woods that are difficult to treat. Pentachlorophenol does not accelerate the corrosion of metal fasteners relative to untreated wood. The heavy oil solvent imparts some water repellency to the treated wood. Treatment facilities in many areas of the United States use pentachlorophenol in heavy oil, making it another readily available wood preservative. Pentachlorophenol is most effective when applied with a heavy solvent, but it performs well in lighter solvents for aboveground applications. Lighter solvents also provide the advantage of a less oily surface appearance, lighter color, and improved paintability. The standards for aboveground minimum retentions for pentachlorophenol vary from 0.25 to 0.3 pounds per cubic foot (4 to 4.8 kilograms per cubic meter) for treatment of red oak to 0.4 pounds per cubic foot (6.4 kilograms per cubic meter) for softwood species. Pentachlorophenol in light oil has some similarities to pentachlorophenol in heavy oil. It can be used to treat species of wood that are difficult to treat and it does not accelerate corrosion. Wood treated with pentachlorophenol in light oil may be used in recreational structures and in applications where human contact is likely, such as handrails, if a sealer such as urethane, shellac, latex, epoxy enamel, or varnish is applied. Wood treated with pentachlorophenol in light oil may be painted or stained after it dries. One disadvantage of the lighter oil is that the treated wood has less water repellency. Treatment facilities that use pentachlorophenol in light oil are not as numerous as those that use heavy oil. Pentachlorophenol is classified as an RUP by the EPA. Producers of treated wood, in cooperation with the EPA, have created consumer information sheets with guidance on appropriate handling and site precautions for wood treated with pentachlorophenol (appendix A). These sheets should be available for all persons who handle wood treated with pentachlorophenol. Pentachlorophenol Pentachlorophenol has been widely used as a pressure-treatment preservative in the United States since the 1940s. The active ingredients, chlorinated phenols, are crystalline solids that can be dissolved in different types of organic solvents. A performance of pentachlorophenol and the properties of the treated wood are influenced by the properties of the solvent. Pentachlorophenol is effective when used in ground contact, freshwater, or aboveground. It is not as effective when used in seawater. A heavy oil solvent (specified as Type A in AWPA Standard P9) is preferable when the treated wood is to be used in ground contact. Wood treated with lighter solvents may not be as durable. Wood treated with pentachlorophenol in heavy oil typically has a brown color, and may have a slightly oily surface that is difficult to paint. It also has some odor, which is associated with the solvent. Pentachlorophenol in heavy oil should not be used when frequent contact with skin is likely (handrails, for instance). Pentachlorophenol in heavy oil has long been a popular choice for treating utility poles, bridge timbers, glue-laminated beams, and foundation pilings. The effectiveness of pentachlorophenol is similar to that of creosote in protecting both hardwoods and softwoods, and pentachlorophenol often is thought to improve the dimensional stability of the treated wood. Pentachlorophenol is listed in the AWPA standards for a wide range of wood products and wood species. The minimum softwood retentions are 0.4 pounds per cubic foot (6.4 kilograms per cubic meter) for wood used aboveground, and 0.5 pounds per cubic foot (8 kilograms per cubic meter) for wood used in critical structural applications or in ground contact.

Copper Naphthenate

 Copper naphthenate is effective when used in ground contact, water contact, or aboveground. It is not standardized for use in saltwater applications. Copper naphthenate effectiveness as a preservative has been known since the early 1900s, and various formulations have been used commercially since the 1940s. It is an organometallic compound formed as a reaction product of copper salts and naphthenic acids derived from petroleum. Unlike other commercially applied wood preservatives, small quantities of copper naphthenate can be purchased at retail hardware stores and lumberyards. Cuts or holes in treated wood can be treated in the field with copper naphthenate. Wood treated with copper naphthenate has a distinctive bright green color that weathers to light brown. The treated wood also has an odor that dissipates somewhat over time. Depending on the solvent used and treatment procedures, it may be possible to paint wood treated with copper naphthenate after it has been allowed to weather for a few weeks. Copper naphthenate can be dissolved in a variety of solvents. The heavy oil solvent (specified in AWPA Standard P9, Type A) or the lighter solvent (AWPA Standard P9, Type C) are the most commonly used. Copper naphthenate is listed in AWPA standards for treatment of major softwood species that are used for a variety of wood products. It is not listed for treatment of any hardwood species, except when the wood is used for railroad ties. The minimum copper naphthenate retentions (as elemental copper) range from 0.04 pounds per cubic foot (0.6 kilograms per cubic meter) for wood used aboveground, to 0.06 pounds per cubic foot (1 kilograms per cubic meter) for wood that will contact the ground and 0.075 pounds per cubic foot (1.2 kilograms per cubic meter) for wood used in critical structural applications. When dissolved in No. 2 fuel oil, copper naphthenate can penetrate wood that is difficult to treat. Copper naphthenate loses some of its ability to penetrate wood when it is dissolved in heavier oils. Copper naphthenate treatments do not significantly increase the corrosion of metal fasteners relative to untreated wood. Copper naphthenate is commonly used to treat utility poles, although fewer facilities treat utility poles with copper naphthenate than with creosote or pentachlorophenol. Unlike creosote and pentachlorophenol, copper naphthenate is not listed as an RUP by the EPA. Even though human health concerns do not require copper naphthenate to be listed as an RUP, precautions such as the use of dust masks and gloves should be used when working with wood treated with copper naphthenate.

Oxine Copper (Copper-8-Quinolinolate)

Oxine copper is effective when used aboveground. Its efficacy is reduced when it is used in direct contact with the ground or with water. It has not been standardized for those applications. Oxine copper (copper-8-quinolinolate) is an organometallic compound. The formulation consists of at least 10-percent copper-8-quinolinolate, 10-percent nickel-2-ethylhexanoate, and 80-percent inert ingredients. It is accepted as a standalone preservative for aboveground use to control sapstain fungi and mold and also is used to pressure-treat wood. Oxine copper solutions are greenish brown, odorless, toxic to both wood decay fungi and insects, and have a low toxicity to humans and animals. Oxine copper can be dissolved in a range of hydrocarbon solvents, but provides protection much longer when it is delivered in heavy oil. Oxine copper is listed in the AWPA standards for treating several softwood species used in exposed, aboveground applications. The minimum specified retention for these applications is 0.02 pounds per cubic foot (0.32 kilograms per cubic meter, as elemental copper).

IPBC and Insecticides

 IPBC (3-iodo-2-propynyl butyl carbamate) is not intended for use in ground contact or for horizontal surfaces that are fully exposed to the weather. It does provide protection for wood that is aboveground and partially protected from the weather3

Some pressure-treating facilities use a mixture of IPBC and an insecticide, such as permethrin or chlorpyrifos, to treat structural members used above ground that will be largely protected from the weather, although this practice is not a standardized treatment. These facilities are using IPBC retentions of 0.035 pounds per cubic foot (0.56 kilograms per cubic meter) or higher, with mineral spirits as the solvent. The advantage of this treatment is that it is colorless and allows the wood to maintain its natural appearance. This treatment is being used on Western species that are difficult to treat. Very few facilities are conducting pressure treatments with IPBC

Alkaline Copper Quaternary (ACQ)

 Compounds Alkaline copper quat (ACQ) is one of the best  wood preservatives that have been developed in recent years to meet market demands for alternatives to CCA. The fungicides and insecticides in ACQ are copper oxide (67 percent) and a quaternary ammonium compound (quat). 

Many variations of ACQ have been standardized or are being standardized. ACQ type B (ACQ–B) is an ammoniacal copper formulation, ACQ type D (ACQ–D) is an amine copper formulation, and ACQ type C (ACQ–C) is a combined ammoniacal-amine formulation with a slightly different quat compound. Wood treated with ACQ–B is dark greenish brown and fades to a lighter brown. It may have a slight ammonia odor until the wood dries. Wood treated with ACQ–D has a lighter greenish-brown color and has little noticeable odor; wood treated with ACQ–C varies between the color of ACQ–B and that of ACQ–D, depending on the formulation. Stakes treated with these three formulations have demonstrated their effectiveness against decay fungi and insects when the stakes contacted the ground. 

The ACQ formulations are listed in the AWPA standards for a range of applications and many softwood species. The listings for ACQ–C are limited because it is the most recently standardized. 

The minimum ACQ retentions are 0.25 pounds per cubic foot (4 kilograms per cubic meter) for aboveground applications, 0.4 pounds per cubic foot (6.4 kilograms per cubic meter) for applications involving ground contact, and 0.6 pounds per cubic foot (9.6 kilo-grams per cubic meter) for highway construction. The different formulations of ACQ allow some flexibility in achieving compatibility with a specific wood species and application. An ammonia carrier improves the ability of ACQ to penetrate into wood that is difficult to treat. For wood species that are easier to treat, such as southern pine, an amine carrier will provide a more uniform surface appearance.

All ACQ treatments accelerate corrosion of metal fasteners relative to untreated wood. Hot-dipped galvanized copper or stainless steel fasteners must be used. The number of pressure-treatment facilities using ACQ is increasing. In the Western United States, the ACQ–B formulation is used because it will penetrate difficult to treat Western species better than other waterborne preservatives. Treatment plants elsewhere generally use the ACQ–D formulation. Researchers at the USDA Forest Service’s Forest Products Laboratory in Madison, WI, are evaluating the performance of a secondary highway bridge constructed using Southern pine lumber treated with ACQ–D (Ritter and Duwadi 1998).

Borates

Borate compounds are the most commonly used unfixed waterborne preservatives. Unfixed preservatives can leach from treated wood. They are used for pressure treatment of framing lumber used in areas with high termite hazard and as surface treatments for a wide range of wood products, such as cabin logs and the interiors of wood structures. They are also applied as internal treatments using rods or pastes. At higher rates of retention, borates also are used as fire-retardant treatments for wood. Boron has some exceptional performance characteristics, including activity against fungi and insects, but low mammalian toxicity. It is relatively inexpensive. Another advantage of boron is its ability to diffuse with water into wood that normally resists traditional pressure treatment. Wood treated with borates has no added color, no odor, and can be finished (primed and painted). While boron has many potential applications in framing, it probably is not suitable for many Forest Service applications because the chemical will leach from the wood under wet conditions. It may be a useful treatment for insect protection in areas continually protected from water. Inorganic boron is listed as a wood preservative in the AWPA standards, which include formulations prepared from sodium octaborate, sodium tetraborate, sodium pentaborate, and boric acid. Inorganic boron is also standardized as a pressure treatment for a variety of species of softwood lumber used out of contact with the ground and continuously protected from water. The minimum borate (B2O3) retention is 0.17 pounds per cubic foot (2.7 kilograms per cubic meter). A retention of 0.28 pounds per cubic foot (4.5 kilograms per cubic meter) is specified for areas with Formosan subterranean termites. Borate preservatives are available in several forms, but the most common is disodium octaborate tetrahydrate (DOT). DOT has higher water solubility than many other forms of borate, allowing more concentrated solutions to be used and increasing the mobility 11 of the borate through the wood. With the use of heated solutions, extended pressure periods, and diffusion periods after treatment, DOT can penetrate species that are relatively difficult to treat, such as spruce. Several pressure treatment facilities in the United States use borate solutions. Although borates have low mammalian toxicity, workers handling borate-treated wood should use standard precautions, such as wearing gloves and dust masks. The environmental impact of borate-treated wood for construction projects in sensitive areas has not been evaluated. Because borate-treated wood is used in areas protected from precipitation or water, little or no borate should leach into the environment. Borates have low toxicity to birds, aquatic invertebrates, and fish. Boron occurs naturally at relatively high levels in the environment. Because borates leach readily, extra care should be taken to protect borate-treated wood from precipitation when it is stored at the jobsite. Precipitation could deplete levels of boron in the wood to ineffective levels and harm vegetation directly below the stored wood. Borate-treated wood should be used only in applications where the wood is kept free from rainwater, standing water, and ground contact

Treatment Processes

Methods that preserve wood generally are either:

• Pressure processes, in which the wood is impregnated in closed vessels at pressures considerably higher than atmospheric pressure

• Processes that do not involve pressure

Pressure Processes

In commercial practice, wood usually is treated by immersing it in preservative in an apparatus that applies high pressure, driving the preservative into the wood. Pressure processes differ in details, but the general principle is the same. The wood is carried on cars or trams into a long steel cylinder, which is closed and filled with preservative. Pressure forces the preservative into the wood until the desired amount has been absorbed and has penetrated relatively deeply. Commonly, three general pressure processes are used: full cell, modified full cell, and empty cell. Commercial treaters often use variations or combinations of these processes. Full-Cell Processes The full-cell (Bethel) process is used when the goal is for wood to retain as much of the preservative as possible. For instance, it is a standard procedure to treat timbers with creosote using the full-cell process to protect the timbers from marine borers. Waterborne preservatives sometimes are applied by the full-cell process. Preservative retention can be controlled by regulating the concentration of the treating solution. The steps in the full-cell process are: 1.Wood is sealed in the treatment cylinder and a preliminary vacuum is applied for a half an hour or longer to remove the air from the cylinder and as much air as possible from the wood.

2.The preservative (at ambient temperature or higher, depending on the system) is pumped into the cylinder without breaking the vacuum.

3.After the cylinder is filled, pressure is applied until the wood will take no more preservative or until the required retention of preservative has been achieved.

4.After pressure has been applied for the specified time, the preservative is pumped from the cylinder.

5.A short final vacuum may be used to remove dripping preservative from the wood

Modified Full-Cell Processes

The modified full-cell process is basically the same as the full-cell process except that it uses lower levels of initial vacuum and often uses an extended final vacuum. The amount of initial vacuum is determined by the wood species, material size, and retention desired. Residual air in the wood expands during the final vacuum to drive out part of the injected preservative solution. For this reason, modified full-cell schedules are sometimes called low-weight schedules. They are now the most common method of treating wood with waterborne preservatives. Empty-Cell Processes The empty-cell process is designed to obtain deep penetration with a relatively low net retention of preservative. The empty-cell process should always be used for treatment with oil preservatives if it provides the desired retention. Two empty-cell processes, the Rueping and the Lowry, are commonly employed; both use the expansive force of compressed air to drive out part of the preservative absorbed during the pressure period. The Rueping empty-cell process, often called the empty-cell process with initial air, has been widely used for many years in Europe and the United States. The following general procedure is employed:

 1.Air under pressure is forced into the treatment cylinder, which contains the wood. The air penetrates some species easily, requiring just a few minutes of application pressure. In treating the more resistant species, the common practice is to maintain air pressure from half an hour to 1 hour before pumping in the preservative, although the need to maintain air pressure for longer than a few minutes does not seem to be fully established. The air pressures employed generally range between 25 to 100 pounds per square inch (172 to 689 kilopascals), depending on the net retention of preservative desired and the resistance of the wood.

2.After the period of preliminary air pressure, preservative is forced into the cylinder. As the preservative is pumped in, air escapes from the treatment cylinder into an equalizing tank (also known as a Rueping tank) at a rate that keeps the pressure constant in the cylinder. When the treatment cylinder is filled with preservative, the treatment pressure is increased above the initial air pressure and is maintained until the wood absorbs no more preservative, or until enough preservative has been absorbed for the required retention of preservative.

3.At the end of the pressure period, the preservative is drained from the cylinder, and surplus preservative is removed from the wood with vacuum. From 20 to 60 percent of the total preservative injected into the cylinder can be recovered after the vacuum has been applied.

Treating Pressures and Preservative Temperatures

The pressures used in treatments vary from about 50 to 250 pounds per square inch (345 to 1,723 kilopascals), depending on the species and the ease with which the wood takes the treatment; pressures commonly range from about 125 to 175 pounds per square inch (862 to 1,207 kilopascals). Many woods are sensitive to (and could be damaged by) high treatment pressures. Heated preservatives are used sometimes to improve penetration, but the elevated temperatures can affect the wood’s properties and the stability of the treatment solution. The AWPA specifications require that the temperature of the preservative during the entire pressure period not exceed 120 degrees Fahrenheit (49 degrees Celsius) for ACC and CCA and 150 degrees Fahrenheit (60 degrees Celsius) for ACQ–B, ACQ–D, ACZA, CBA–A, CA–B, and CDDC. The maximum temperature for inorganic boron is 200 degrees Fahrenheit (93 degrees Celsius). Please refer to the Wood Handbook for more information on treating pressures and temperatures. Penetration and Retention Penetration and retention requirements are equally important in determining the quality of preservative treatment. Penetration levels vary widely, even in pressure-treated material. In most species, heartwood is more difficult to penetrate than sapwood. In addition, species differ greatly in the degree to which their heartwood may be penetrated. Incising (perforating the surface of the wood with small slits) tends to improve the penetration of preservative in many refractory species, but species that are highly resistant to penetration will not have deep or uniform penetration, even when they are incised. When the heart faces of these species are not incised, penetration may be as deep as 1⁄ 4 inch (6 millimeters), but often is not more than 1⁄ 16 inch (1.6 millimeters).

Non pressure Processes

The numerous non pressure processes differ widely in the penetration and retention levels that may be achieved and in the degree of protection they provide. When similar retention and penetration levels are reached, the service life of wood treated by a non pressure method should be comparable to that of wood treated by a process that uses pressure. Nevertheless, non pressure treatments, particularly those involving surface applications, generally do not produce results as satisfactory as those produced by pressure treatments. The non pressure processes do serve a useful purpose when more thorough treatments are impractical or when little protection is required.

In general, non pressure methods consist of:

• Surface application of preservatives by brushing or brief dipping

 • Soaking wood in preservative oils or steeping it in solutions of waterborne preservatives

• Diffusion processes using waterborne preservatives

• Vacuum treatment

 • Other miscellaneous processes 

Surface Applications The simplest treatment is to dip wood into preservative or to brush preservative on the wood. Preservatives that have low viscosity when cold should be used, unless the preservative can be heated. The preservative should be flooded over the wood rather than merely painted. Every check and depression in the wood should be thoroughly filled with the preservative. Any untreated wood that is left exposed will provide ready access for fungi. Rough lumber may require as much as 10 gallons of oil per 1,000 square feet (40 liters of oil per 100 square meters) of surface. 

Surfaced lumber requires considerably less oil. The transverse penetration usually will be less than 1⁄ 10 inch (2.5 millimeters), although in easily penetrated species, end-grain (longitudinal) penetration will be considerably deeper. The additional life obtained by such treatments will be affected greatly by the conditions of service. For treated wood that contacts the ground, service life may be from 1 to 5 years. Dipping wood for a few seconds to several minutes in a preservative provides more assurance that all surfaces and checks will be thoroughly coated with the preservative. In addition, dipping usually produces slightly deeper penetration. Window sashes, frames, and other millwork commonly are treated by dipping them in a water-repellent preservative, either before or after assembly. Transverse penetration of the preservative applied by brief dipping is very shallow, usually less than a few hundredths of an inch (a millimeter). The exposed end surfaces at joints are the most vulnerable to decay in millwork products. Good end-grain penetration is especially important. Dip applications provide very limited protection to wood that contacts the ground or that is used in very moist conditions. They provide very limited protection against attack by termites. However, they do have value for exterior woodwork and millwork that is painted, that does not contact the ground, and that is exposed to moisture just for brief periods.

Thermal process treatment consists of immersing wood alternately in separate tanks containing heated and cold preservative, either oil- or waterborne (or in one tank which is first heated than allowed to cool). During the hot bath, air in the wood expands and some is forced out. Heating improves penetration of preservatives. In the cold bath, air in the wood contracts, creating a partial vacuum, and atmospheric pressure forces more preservative into the wood. Temperature is critical; only use preservatives that can safely be heated.

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