Overview of Countermeasures Regarding Sick House Issues under the Amended
 
Building Standard Law
  
     
News
   Overview  
  (1) Chemical substances covered by regulations
Chlorpyrifos and formaldehyde
(2) Regulations concerning chlorpyrifos
The use of building materials containing chlorpyrifos in buildings with habitable rooms will be prohibited.
(3) Regulations concerning formaldehyde
          1) Restrictions on interior finishing materials
The area size of formaldehyde-emitting building materials which can be used as interior finishing materials will be restricted according to the type of habitable room and the frequency of ventilation.
          2) Mandatory installation of ventilation equipment
Even if no formaldehyde-emitting building materials are used, formaldehyde is also emitted by furniture. For this reason, the installation of ventilation equipment will, in principle, be mandatory in all buildings.
          3) Restrictions related to ceiling cavities, etc.*
The base materials used in ceiling cavities, etc., must have low formaldehyde emission levels, or ventilation equipment must be designed to allow ventilation of ceiling cavities, etc.
* Ceiling cavities, etc. includes ceiling cavities, attics, cavities underneath floors, wall, storerooms and other similar locations.
 
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
  Illustrations Showing Possible Countermeasures for Different Housing Types Flow of the Requirements
       
  Basic Technical Criteria (Cabinet Order*, Notifications) for Countermeasures Regarding Sick House Issues
  * Cabinet Order: The Building Standard Law Enforcement Order (hereinafter referred to as the Order)

1. Chemical substances subjected to regulations
The chemical substances stipulated in the Order are chlorpyrifos and formaldehyde.
2. Regulations on building materials in relation to chlorpyrifos
The use of building materials containing chlorpyrifos in buildings is prohibited.
* Building materials containing chlorpyrifos is exempted if they have been used as building parts for five years or more.
3. Regulations concerning building materials and ventilation equipment in relation to formaldehyde
     (1) Restrictions on interior finishing materials
      1) Categories of building materials
 
  *1 Measurement conditions
Temperature: 28oC, relative humidity: 50%, formaldehyde density: 0.1 mg/m3 (=guideline value announced by MOHLW)
*2 There are no restrictions on materials which have been used as parts of buildings for five years or more.
 








       2) Prohibition on use of type 1 formaldehyde-emitting building materials
The use of type 1 formaldehyde-emitting building materials as interior finishing materials in habitable rooms is prohibited.
* Habitable rooms also include other areas of buildings, such as corridors, which have permanent openings (such as door undercuts) and which are ventilated together with the habitable rooms according to ventilation planning. (The same applies below.)
* Interior finishing materials are materials applied to the surfaces of walls, floors and ceilings (excluding picture rails, windowsills and similar parts). Pillars and other framing lumber, baseboards, handrails, head jambs, lintel joist, and other finishing trim, window/door trim and paints adhesives, etc used in small quantities are excluded. (The same applies below.)
     3) Restrictions on use of type 2 and type 3 formaldehyde-emitting building materials
The use of type 2 and type 3 formaldehyde-emitting building materials as interior finishing materials in habitable rooms is limited to area size which satisfy the following formula.
 
 
  *1 Habitable rooms in houses, etc., are habitable rooms in houses, bedrooms in boarding houses, bedrooms in dormitories, and sales areas in stores engaged in commodity sales such as furniture and similar items.
*2 Ventilation includes ventilation achieved by using construction methods stipulated or approved by the Minister of Land, Infrastructure and Transport as providing a ventilation frequency equivalent or superior to mechanical ventilation equipment providing the ventilation frequency shown in the above table.
        4) Exemptions
      The following types of habitable rooms are covered by other criteria, etc., and are therefore       exempted from the restrictions concerning interior finishing materials specified herein.
          • Habitable rooms equipped with centrally controlled air conditioning equipment which           complies with specific criteria (Article 20-6, paragraph 1 item (1) (c) of the Order)
          • Habitable rooms approved by the Minister of Land, Infrastructure and Transport as rooms in           which it is possible to maintain the density of formaldehyde at no more than 0.1 mg/m3           throughout the year in areas where people can be expected to engage in normal activities.           (Note: Such rooms are also exempted from the criteria concerning ventilation equipment.)

     (2) Mandatory installation of ventilation equipment
      1) Installation of one of the following types of ventilation equipment is mandatory.
 
  *1 When one mechanical ventilation system is used to ventilate two or more habitable rooms, its effective ventilation capacity must be equal to or greater than the total required ventilation capacity for all of the rooms.
*2 The control and operational status of mechanical ventilation equipment installed in buildings, etc., in which an emergency elevator is required to be installed (except equipment used to ventilate individual habitable rooms) or the monitoring of centrally controlled air conditioning equipment must be possible from a central control room.

     2) Cases in which general mechanical ventilation equipment is not required
The following types of habitable rooms do not require ventilation equipment which complies with the requirements in 1).
  a. Habitable rooms in which ventilation is provided through openings and gaps (equivalent to a ventilation frequency of 0.5 times/hour)
• Habitable rooms in which the total area of openings and gaps which are always open to the outside air and which are effective for ventilation is at least 15 cm2 per square meter of floor area
• Habitable rooms other than those used for sleeping (e.g. habitable rooms in houses, bedrooms in hotels, inns and boarding houses) in which the total area of openings and gaps which are open to the outside air and which are effective for ventilation when the room is in use is at least 15 cm2 per square meter of floor area
• Habitable rooms in buildings of "shinkabe" construction in which no plywood or similar panel-like building material is used for exterior walls, ceilings and floors
• Habitable rooms in buildings of "shinkabe" construction in which no plywood or similar panel-like building material is used for exterior walls, and in which the fixture fittings on openings in exterior walls are wooden frames and have gaps through which ventilation can be provided
  b. Easing of ventilation frequency requirements for habitable rooms with high ceilings
• Habitable rooms in which the ceiling is above a certain height, and in which there is mechanical ventilation equipment providing effective ventilation capacity or equivalent effective ventilation capacity as stipulated in the following tables according to ceiling height
  Habitable rooms (ceiling height 2.7 m or higher) with ventilation provided at the equivalent of 0.7 times/h
 
  Habitable rooms (ceiling height 2.9 m or higher) with ventilation provided at the equivalent of 0.5 times/h
 
  Habitable rooms (ceiling height 3.5 m or higher) with ventilation provided at the equivalent of 0.3 times/h
 
    c. Habitable rooms approved by the Minister of Land, Infrastructure and Transport as rooms in which it is possible to maintain the concentration of formaldehyde at no more than 0.1 mg/m3 throughout the year in areas where people can be expected to engage in normal activities. (Note: Such rooms are also exempted from restrictions concerning the use of building materials.)
       (3) Restrictions concerning ceiling cavities, etc.
Where mechanical ventilation equipment or centrally controlled air conditioning equipment has been installed, one of the following measures must be implemented to prevent formaldehyde entering habitable rooms from ceiling cavities, etc. (ceiling cavities, attics, cavities underneath floors, wall, storerooms and other similar locations):
     1) Controlling the emission of formaldehyde which might flow into habitable rooms through non-use of the following materials as base materials, thermal insulation materials or other similar surface materials, in ceiling cavities, etc.:
- Type 1 formaldehyde-emitting building materials
- Type 2 formaldehyde-emitting building materials
- Building materials approved by the Minister of Land, Infrastructure and Transport under the provisions of Article 20-5 paragraph 2 of the Order (building materials deemed to be equivalent to type 2 formaldehyde-emitting building materials)
     2) Controlling the flow of formaldehyde into habitable rooms through use of airtight layers or seals. The locations in which countermeasures are implemented are as follows:
- Areas facing the outside, other than separation walls which are separated from a habitable room with a continuous airtight layer, using airtight materials as stipulated in the "Design and Construction Guidelines for the Rationalization of Energy Use in Houses," based on Ministry of Construction Notification No. 998 of 1999, under the Law Concerning the Rationalization of Energy Use (Law No. 49 of 1979, known as the "Energy Conservation Law") (referred to below as "airtight materials")
- Parts of walls, etc., in which air seals are applied to all necessary locations using airtight materials or materials with airtightness equivalent or superior to that of airtight materials (e.g. plasterboard) to control the flow of formaldehyde into habitable rooms by preventing the passage of air between habitable rooms and other areas.
     3) For ceiling cavities, etc., where the countermeasures described in 1) or 2) have not been implemented limiting formaldehyde flowing into habitable rooms due to air pressure differentials by measures based on the use of mechanical ventilation equipment, etc., to maintain the air pressure in habitable rooms at a higher level than in ceiling cavities, etc..
Depending on the type of mechanical ventilation equipment, etc., the following specific measures might be used for this purpose:
- Type 1 ventilation equipment (equipment with air supply and exhaust systems)
The air pressure in the habitable rooms shall be maintained above the pressure in the ceiling cavities, etc., by adjusting the capacities of the air supply and exhaust systems. Alternatively, an exhaust system installed in a habitable room or another exhaust system may be used to exhaust air from the ceiling cavities, etc.
- Type 2 ventilation equipment (equipment with an air supply system and an air outlet)
Since air supply is provided mechanically, no other special measures are required.
- Type 3 ventilation equipment (equipment with an air inlet and an exhaust system)
An exhaust system installed in a habitable room or another exhaust system may be used to exhaust air from the ceiling cavities, etc.
 
April 9, 2003
Ministry of Land, Infrastructure and Transport
Architectural Guidance Division