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Related Laws and Regulations (Building Standards Act, Construction Business Act, Labor Standards Act, Vocational Ability Development Promotion Act)

Rebar Worker Certificate 鉄筋技能士 (Grade 1/2 theory) · 技能検定「鉄筋施工」1級・2級 学科 · Written by Tokutei Pass based on the official study texts; not copied verbatim.

Purpose of the Building Standards Act and Key Statutory Definitions

Article 1 of the Building Standards Act establishes the 'minimum standards' for the site, structure, equipment, and use of buildings in order to protect the life, health, and property of citizens and promote public welfare.

Under Article 2, 'building activity (kenchiku)' means 'new construction (shinchiku), extension (zōchiku), rebuilding (kaichiku), or relocation (iten)'; major remodeling (moyōgae) and repair (shūzen) are not included in the definition of 'kenchiku.' Schools, hospitals, theaters, department stores, apartment buildings, and factories are defined as 'special buildings (tokushu kenchikubutsu).'

'Principal building parts (shuyō kōzōbu),' used primarily for fire-resistance regulations, mean walls, columns, floors, girders, roofs, or stairs, excluding structurally non-essential partition walls, lowest-story floors, secondary beams (kobari), eaves (hisashi), and minor local stairs (foundations are also excluded).

By contrast, 'structurally principal load-bearing parts (kōzō tairyoku-jō shuyō na bubun)' (Enforcement Order Article 1) include foundations, foundation piles, walls, columns, roof trusses, sills, diagonal braces, floor slabs, roof slabs, and horizontal framing members (girders and beams) that support dead load, live load, wind pressure, earth pressure, and seismic forces.

Key points


  • The Building Standards Act sets 'minimum standards,' and 'building activity (kenchiku)' comprises new construction, extension, rebuilding, and relocation

  • 'Principal building parts (shuyō kōzōbu)' are walls, columns, floors, girders, roofs, and stairs (excluding foundations, lowest-story floors, secondary beams, and eaves)

  • 'Structurally principal load-bearing parts' include foundations, piles, walls, columns, floor/roof slabs, and horizontal members (girders/beams)
WordMeaning
Building Standards Act (minimum standards)
building activity (new construction, extension, rebuilding, relocation)
principal building parts (excluding lowest floor and secondary beams)
structurally principal load-bearing parts (foundations, columns, girders)

Building Confirmation, Interim Inspection, and Completion Inspection Procedures

Before starting construction of a building above specified thresholds (such as an RC building exceeding 200 m² in total floor area, or construction within city planning areas), the building owner must apply to a Building Official or designated confirmation agency and receive a 'Confirmation Certificate (Kakuninzumi-shō)' prior to commencing work.

Under Article 7-3 of the Building Standards Act, the 'stage of placing floor and beam reinforcement in an apartment building having 3 or more stories' and other stages designated by the administrative authority (such as foundation rebar completion) are designated as 'Specified Stages (Tokutei Kōtei).'

Upon completing a Specified Stage, the work must undergo an 'Interim Inspection (Chūkan Kensa),' and subsequent stages such as concrete placement cannot proceed until an 'Interim Inspection Pass Certificate (Chūkan Kensa Gōkakushō)' has been issued.

Upon completion of the entire work, an application for 'Completion Inspection (Kanryō Kensa)' must reach the authority within 4 days from the date of completion to obtain the 'Inspection Certificate (Kensazumi-shō).' A confirmation sign board must also be posted in a visible location on site.

Key points


  • Construction cannot begin until a Building Confirmation application is approved and a 'Confirmation Certificate' is issued

  • For 'Specified Stages' (such as floor/beam rebar placement in apartment buildings of 3+ stories), subsequent work cannot proceed until an 'Interim Inspection Pass Certificate' is issued

  • Completion Inspection must be applied for within '4 days' after work completion to receive the 'Inspection Certificate'
WordMeaning
Building Confirmation application and Confirmation Certificate
Specified Stage (floor/beam rebar in 3+ story apartment buildings, etc.)
Interim Inspection and Interim Inspection Pass Certificate
Completion Inspection (within 4 days) and Inspection Certificate

Concrete Materials, Strength, Curing, and Formwork Removal (Order Articles 72 & 74–76)

Article 72 of the Building Standards Act Enforcement Order stipulates that water and aggregates used in reinforced concrete 'must not contain acid, salt, organic matter, or mud that would corrode reinforcing bars or hinder the setting and hardening of concrete,' and aggregates must be of a size that 'passes easily between reinforcing bars and between the bars and the formwork sheathing.'

Article 74 requires the 4-week (28-day) compressive strength of concrete to be 'at least 12 N/mm² (or at least 9 N/mm² when lightweight aggregate is used)' and at least equal to the specified design strength.

Article 75 (Curing of Concrete) stipulates that 'during placement and for 5 days after placement, concrete must be cured so that its temperature does not fall below 2°C, and protected against drying and vibration that would impair setting and hardening.'

Article 76 (Removal of Formwork and Shoring) mandates that formwork and shoring for structurally principal load-bearing parts 'must not be removed until the concrete has reached sufficient strength to prevent significant deformation, cracking, or damage under its own weight and construction loads.'

Key points


  • Order Article 72: Aggregates must pass between rebars and formwork cover and be free of harmful acid, salt, organic matter, or mud

  • Order Article 74: 4-week concrete compressive strength must be 'at least 12 N/mm² (9 N/mm² for lightweight aggregate)'

  • Order Article 75: Concrete temperature must be maintained at '2°C or above' during placement and for '5 days' afterward
WordMeaning
Order Article 72 (aggregate size and prohibition of harmful substances)
Order Article 74 (4-week compressive strength ≥ 12 N/mm²)
Order Article 75 (curing at ≥ 2°C for 5 days after placement)
Order Article 76 (restrictions on formwork and shoring removal)

Splices and Anchorage of Reinforcing Bars (Enforcement Order Article 73)

Article 73, Paragraph 1 of the Building Standards Act Enforcement Order states: 'The ends of reinforcing bars must be bent into hooks and anchored so that they do not pull out of the concrete; provided, however, that when deformed bars are used in parts other than chimneys, their ends need not be bent into hooks.'

Consequently, whenever plain round bars (marukō) are used, end hooks are mandatory without exception, and for reinforcing bars in chimneys (entotsu), end hooks are mandatory even when deformed bars are used.

Paragraphs 2 to 4 of Article 73 govern splices in main bars and shear wall bars: splices must in principle be placed where tensile force in the member is smallest, and must either have the required lap splice length or use welded/mechanical joints with strength at least equal to the parent bar.

Furthermore, when anchoring column main bars into foundations or beam main bars into columns, the prescribed development length must be secured to reliably transfer tensile forces.

Key points


  • Order Article 73(1): Rebar ends must have hooks in principle, except that end hooks may be omitted when 'deformed bars are used in parts other than chimneys'

  • End hooks cannot be omitted for 'plain round bars' or for 'reinforcing bars in chimneys'

  • Main-bar splices must be placed where tensile stress is smallest, and welded or mechanical splices must have strength at least equal to the base metal
WordMeaning
Order Article 73 (rebar splices and anchorage)
hook-shaped bend (end hook)
hook-omission rule for deformed bars (except chimneys)
placing splices where tensile force is smallest

Structural Requirements for Columns (Enforcement Order Article 77)

Article 77 of the Building Standards Act Enforcement Order sets out items (1) through (6) governing the minimum reinforcement and geometry of structurally principal 'columns (hashira)'—one of the most frequently tested articles on the written exam.

Items (1) and (2) require that 'main reinforcing bars must be 4 or more in number and securely tied to hoops (obikin),' while Item (6) requires that 'the total cross-sectional area of the main bars must be at least 0.8% of the gross concrete cross-sectional area.'

Items (3) and (4) govern column hoops: hoop diameter must be 'at least 6 mm,' and hoop spacing (pitch) must be '10 cm or less AND 15 times the diameter of the smallest main bar or less' (outside the end zones of twice the minimum column dimension from top and bottom, the 10 cm limit may be relaxed to 15 cm if hoop reinforcement is increased accordingly).

In addition, Item (4) requires a 'hoop reinforcement ratio (obikin-hi) of at least 0.2%,' and Item (5) requires the minimum lateral dimension of the column to be 'at least 1/15 of the distance between principal structural supports (or at least 1/10 for lightweight concrete).'

Structural Requirements for Columns (Enforcement Order Article 77)

Key points


  • Order Article 77 (Columns): Main bars must be '4 or more,' tied to hoops, with total main-bar area 'at least 0.8%' of concrete area

  • Column hoop diameter must be 'at least 6 mm,' with spacing '10 cm or less AND 15 times the smallest main-bar diameter or less'

  • Column hoop ratio must be 'at least 0.2%,' and smallest column width must be 'at least 1/15 of support span'
WordMeaning
Order Article 77 (column structure)
4 or more main bars; main-bar ratio ≥ 0.8%
hoop diameter ≥ 6 mm; spacing ≤ 10 cm and ≤ 15× smallest main bar
hoop ratio ≥ 0.2%; minimum column dimension ≥ 1/15

Structural Requirements for Beams and Bearing Walls (Order Articles 78 & 78-2)

Article 78 of the Building Standards Act Enforcement Order stipulates for structurally principal 'beams (hari)' that 'beams must be doubly reinforced (fukukin-bari) and provided with stirrups (abarakin) spaced at no more than 3/4 of the beam depth (and up to 30 cm in principle).'

Furthermore, beam stirrup diameter must be 'at least 6 mm' and the stirrup reinforcement ratio must be 'at least 0.2%' (in JASS 5 and the Public Building Standard Specifications, deformed bars of D10 or larger at ≤ 25 cm or ≤ 20 cm pitch are commonly required).

Next, Article 78-2 stipulates for 'bearing walls (shear walls, tairyoku-heki)' that: (1) wall thickness must be 'at least 12 cm,' and (2) reinforcing bars of 'at least 12 mm' in diameter must be placed around wall openings.

In addition, bearing-wall web reinforcement must consist of bars 'at least 9 mm' in diameter spaced vertically and horizontally at '30 cm or less (or 45 cm or less when arranged as double-layer reinforcement on both wall faces)' and anchored into the surrounding columns and beams.

Key points


  • Order Article 78 (Beams): Doubly reinforced beams with stirrups '≥ 6 mm' in diameter, spacing '≤ 3/4 of beam depth (≤ 30 cm),' and stirrup ratio '≥ 0.2%'

  • Order Article 78-2 (Bearing Walls): Thickness '≥ 12 cm,' with opening trim bars '≥ 12 mm' in diameter around openings

  • Bearing-wall bars must be '≥ 9 mm' in diameter, spaced vertically and horizontally at '≤ 30 cm' (single layer) or '≤ 45 cm' (double layer)
WordMeaning
Order Article 78 (doubly reinforced beam; stirrup diameter ≥ 6 mm)
stirrup spacing (≤ 3/4 beam depth; ≤ 30 cm)
Order Article 78-2 (bearing wall thickness ≥ 12 cm; opening trim bar ≥ 12 mm)
bearing-wall bars (diameter ≥ 9 mm; pitch ≤ 30 cm; double layer ≤ 45 cm)

Minimum Concrete Cover Thickness (Enforcement Order Article 79)

Article 79 of the Building Standards Act Enforcement Order strictly specifies the statutory 'minimum concrete cover thickness (saishō kaburi atsusa)' over reinforcing bars in four tiers (2 cm, 3 cm, 4 cm, and 6 cm) according to member type and soil contact.

First, 'non-bearing walls or floors (slabs, stairs, etc.)' not in direct contact with soil require 'at least 2 cm.' Second, 'bearing walls, columns, or beams' not in direct contact with soil require 'at least 3 cm.'

Third, 'walls, columns, floors, or beams in direct contact with soil' and the 'upstand stem of a continuous strip footing (nunogiso no tachiagari)' require 'at least 4 cm.' Fourth, 'foundations (excluding the upstand stem of a continuous strip footing)' require 'at least 6 cm,' excluding any blinding concrete (sute-konkurīto).

Note that Article 79 specifies the statutory absolute minimum cover; in actual construction (JASS 5 and Public Building Standard Specifications), a construction margin of 10 mm (or 10–20 mm) is added to establish the 'design cover thickness' used to select spacers. Blinding concrete thickness is never counted toward the 6 cm foundation cover.

Minimum Concrete Cover Thickness (Enforcement Order Article 79)

Key points


  • Not in contact with soil: 'non-bearing walls and floors' ≥ 2 cm; 'bearing walls, columns, and beams' ≥ 3 cm

  • 'Walls, columns, floors, or beams in direct contact with soil' and 'strip-footing upstand stems' ≥ 4 cm

  • 'Foundations (excluding strip-footing upstands)' ≥ 6 cm, excluding blinding concrete
WordMeaning
Order Article 79 (minimum concrete cover thickness)
indoor floors/non-bearing walls (≥ 2 cm) and bearing walls/columns/beams (≥ 3 cm)
soil-contact walls/columns/floors/beams and strip-footing upstands (≥ 4 cm)
foundations (≥ 6 cm excluding blinding concrete)

Construction Business Act, Labor Standards Act, and Vocational Ability Development Promotion Act

The Construction Business Act classifies construction work into 2 general categories and 27 specialist trades (29 categories total), defining 'Rebar Work (Tekkin Kōji)' as the processing, joining, and assembly of steel bars. Construction contracts must be executed in writing, 'blanket subcontracting (ikkatsu shitaukeoi)' is prohibited in principle, and a 'Chief Engineer (shunin gijutsusha)' or 'Managing Engineer (kanri gijutsusha)' must be assigned to manage technical execution on site.

The Labor Standards Act sets statutory working hours (excluding rest periods) at '8 hours per day and 40 hours per week,' requiring at least 45 minutes of rest for work exceeding 6 hours and at least 1 hour of rest for work exceeding 8 hours.

Under Article 62 of the Labor Standards Act, minors under 18 years of age are prohibited from engaging in hazardous duties such as 'work at heights of 5 m or more where there is a risk of falling,' 'crane operation or slinging (tamagake),' and 'scaffolding erection or dismantling.'

Under the Vocational Ability Development Promotion Act, persons who pass the National Trade Skill Test may use the title 'Certified Rebar Skilled Worker (Tekkin Ginōshi).' Grade 1 certificates are issued by the 'Minister of Health, Labour and Welfare,' while Grade 2 and Grade 3 certificates are issued by the 'Prefectural Governor.' Non-certified persons are legally prohibited from using the title Ginōshi.

Key points


  • The Construction Business Act prohibits 'blanket subcontracting' and requires placement of a 'Chief Engineer (or Managing Engineer)' on site

  • The Labor Standards Act sets statutory hours at '8 hours/day and 40 hours/week' and prohibits minors under 18 from working at heights ≥ 5 m or performing slinging

  • Under the Vocational Ability Development Promotion Act, Grade 1 certificates are issued by the 'Minister of Health, Labour and Welfare' and Grade 2/3 by the 'Prefectural Governor,' with title protection for 'Ginōshi'
WordMeaning
Construction Business Act (Chief Engineer and ban on blanket subcontracting)
Labor Standards Act (8 hours/day, 40 hours/week)
hazardous-work restrictions for minors (under 18 years old)
Vocational Ability Development Promotion Act and Certified Rebar Skilled Worker

Official references

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