|4 Building Materials and Furniture and Reduction Countermeasures against Indoor Air Chemicals|
Strategic Planing Division of Building Products CompanyMatsusita Electric Works Ldt.
In June 1996, the Sick Building Problem was made public. Subsequently, attention has been drawn to “Sick Building” and “Sick School” problems at public buildings including schools and kindergartens.
Factors that cause “Sick Building Syndrome” include: decreased body resistance compared with before; inadequate air clarification as airtightness and adiabaticity of residential housing become high; many processed products made from chemical materials, such as daily necessities, are brought into rooms.
On the other hand, direct factors of “Sick Building Syndrome” indicate that chemicals used during manufacturing of building materials and furniture or residual volatile organic compounds (VOC) in daily necessities are diffused into a room.
1. Building materials, furniture and volatile organic compounds (VOC)
Building materials and furniture which are commonly used are usually processed products from wood-based materials. After the surfaces of wood-based materials, such as plywood and fiberboard, are processed, wall and floor materials, kitchen and storage cabinets, desks and chairs are assembled using building materials and furniture. Some of the major adhesive agents used for wood-based materials during manufacturing include formaldehyde. The materials bring about formaldehyde emissions. Also, when wood-based materials are processed, adhesive agents and solvents used lead to toluene and xylene emissions.
2. Regulation or removal of indoor air quality pollutants
In arguing about contamination of indoor air quality by VOC, the indoor concentration guideline values released by the Ministry of Health, Labour and Welfare is used as a guideline for evaluating the degree of pollution. This guideline value is quoted in various scenes as one of the bases of regulation for causative substance removal.
A subsequent regulation is the Housing Performance Indication System enforced in 2000 by the Ministry of Land, Infrastructure and Transport. With respect to “Air quality performance”, which is one of the performance items, a performance rating depending on a formaldehyde performance rating of building materials used was introduced. Also, in 2001, regarding the five substances such as formaldehyde, toluene, xylene, ethylbenzene and styrene, the item on “concentration of indoor air chemicals” was added as a selective item.
Subsequently, revision of the building standards law related to Sick Building, which went into effect July 1st, 2003, had a great influence on the housing industry.
VOCs targeted by the revised law are formaldehyde and chlorpyrifos.
There are three essential features of regulations for formaldehyde. First, occupancy area restrictions are received depending on formaldehyde emission grade when building materials with formaldehyde emissions specified by law are used for the living room. Second, 24- hour operative type ventilation equipment in all the living rooms of a building is installed. Third, one of the following two measures is performed: building materials with formaldehyde emissions more than the specified grade are used under the roof, or ventilation equipment is installed.
Especially, with respect to building materials with formaldehyde emissions, three grades (Ｆ☆☆☆☆, Ｆ☆☆☆, Ｆ☆☆), depending on the amount of formaldehyde emissions, were established in the Japanese Industrial Standards (JIS) and the Japan Agricultural Standards (JAS). When building materials with formaldehyde emissions are used indoor based on every grade, it is specified that several times of a floor area must be used.
Regulation of chlorpyrifos indicates a total ban on the use of building materials using this agent.
Regarding furniture, assuming that products are manufactured from the materials that are graded more thanＦ☆☆☆, furniture itself is not regulated.
3. Concrete measures for reduction in VOC emissions
As a concrete measure for reduction in VOC emissions, all of the chief materials, such as wood-based materials used, and all sub materials, like adhesive agents and paint, are changed into materials of the F☆☆☆☆ level established by the new regulations and then the process is finished.
In addition, as a definitive measure for reduction in emissions of other volatile organic compounds, such as toluene and xylene, converting the adhesives and paint used in manufacturing building materials or household equipment into water-soluble products is conducted. The furniture industry also works on the reduction of VOC emissions with all hands on deck.
4. Effects after reduction countermeasures
At around the start of the revised law, products in the market for building materials and equipment have been changed into the lowest emission F☆☆☆☆ products of formaldehyde. Products less thanＦ☆☆☆ are rarely distributed.
On the other hand, the Ministry of Land, Infrastructure and Transport has continuously implemented an actual condition survey of the chemical substance concentrations in indoor air since 2000. Residential housing exceeding the indoor concentration guideline values established by the Ministry of Health, Labour and Welfare tends to decrease every year. Also, formaldehyde concentrations in new residential housing are distributed on the lower concentration side (Table 1).
The effect of the revised building standards law is clearly visible.
The status of emission reduction from building materials, household equipment and furniture from formaldehyde, which is the main causative substance of indoor air pollutants, has greatly improved due partly to regulation by the revised Building Standard Law.
Converting toluene, xylene, ethylbenzene and styrenen, which are assumed to be emitted from building materials and furniture, into non-solvent adhesives and paint for emission control of VOC is progressing.
At any rate, reduction of VOC, which is a contamination source of indoor air quality, from building materials and furniture is what we must solve. Much more effort from the individuals concerned is earnestly expected.
Measures against indoor air pollution and health for children
1 Challenges and the Present Condition of Countermeasures against Indoor Air Chemicals
2 Children’s Environmental Health and Countermeasures against Indoor Air Chemicals
3 Measurement and Evaluation for the Determination of Indoor Air Chemicals
4 Building Materials and Furniture and Reduction Countermeasures against Indoor Air Chemical
5 Daily Life of a Patient with Multiple Chemical Sensitivity