2026-10-24T09:22:36

SNI 8640 Lightweight Brick Standard: Classes, Minimum Strength and Sizes

SNI 8640 lightweight brick requirements (SNI 8640:2018) are Indonesia's national standard for lightweight bricks used in wall masonry, covering AAC (hebel), CLC and lightweight-aggregate bricks with a density of 400–1,400 kg/m³. The key points for buyers: class I may be used for structural walls in houses of up to two storeys, class II only for non-structural walls, and the minimum average compressive strength is 6, 4 or 2 MPa depending on the class. Ask for the SPPT SNI certificate and test figures, not just an "SNI" claim.

SNI 8640 lightweight brick: a worker building a lightweight concrete block wall on a house project

SNI 8640 lightweight brick classes and groups

The standard divides lightweight bricks into two classes. Class I is structural brick, which according to the SNI may only be used in buildings of up to two storeys and with tie beams. Class II is non-structural brick. Class I bricks may be used as class II, but not the other way round. Each class is further split into two groups: group A for exposed walls, including bathrooms, and group B for interior walls.

Main physical requirements (Table 3)

Class	Min. average compressive strength	Min. individual compressive strength
I A	6 MPa	5.4 MPa
I B	4 MPa	3.6 MPa
II	2 MPa	1.8 MPa

The same table limits water absorption to 25 % by volume for exposed groups and drying shrinkage to 0.2 %. The water absorption requirement may be waived if the outer face of the wall is covered with waterproof plaster or panels in line with ASTM C1692.

Standard sizes and weight

Table 1 of the standard lists the common size of 600 x 200 mm with a tolerance of +3/−5 mm, and thicknesses of 75, 100, 125 and 150 mm with a tolerance of ±2 mm. Weight categories are 500, 700, 900, 1,100 and 1,300 kg/m³. The 75 mm thickness is only for partitions inside one dwelling unit; walls between apartment units must be at least 100 mm thick. For mortar, the standard gives a joint thickness of 7–10 mm for conventional mortar and 1.5–3.0 mm for thin-bed adhesive.

The standard also asks producers to provide information on fire resistance, thermal properties and sound insulation. For example, the Blesscon brochure (PT Superior Prima Sukses Tbk) lists a normal density of 600 kg/m³, compressive strength above 4.0 N/mm², thermal conductivity of 0.14 W/mK and sound insulation of 41–48 dB. The brochure also gives wall area per m³: 13.33 m² for 7.5 cm, 10 m² for 10 cm, 8 m² for 12.5 cm, 6.67 m² for 15 cm and 5 m² for 20 cm. According to a company release dated 14 December 2022, Blesscon holds SNI 8640:2018 and SNI 2156:2021 (autoclaved aerated concrete) certificates. The brochure does not state the SNI 8640 class of the product.

How to check SNI 8640 lightweight brick certificates

Ask for a copy of the SPPT SNI. The IAPMO Indonesia scheme says certificates are valid for up to 4 years, with surveillance audits in months 12, 24 and 36.
Check the test parameters: dimensions, weight, surface, compressive strength, thickness and drying shrinkage.
Get the class and group in writing, especially if the wall carries load.
For your own tests, the standard sets sample sizes: up to 10,000 pieces, take 10; 10,001–100,000 pieces, take 20.

Order lightweight bricks through homeX

homeX is a one-stop building materials and furniture platform in Indonesia with a showroom, warehousing and delivery. Send the thickness, volume in m³ and project location via WhatsApp +62 821 1818 998; we can help compare brands and their SNI documents. homeX showroom: Priskilla Tower 6th floor, Jl. Atang Sanjaya No.21, Benda, Kota Tangerang, Banten 15125. Visit the homeX showroom.

Note: this summary does not replace the full SNI document or structural calculations by an engineer. Product data comes from the manufacturer's brochure; confirm before buying. Data as of 24 October 2026.

FAQ

What is the minimum compressive strength of lightweight bricks under SNI 8640? The minimum average is 6 MPa for class I group A, 4 MPa for class I group B and 2 MPa for class II, with minimum individual values of 5.4, 3.6 and 1.8 MPa.

Can lightweight bricks be used for structural walls? Under SNI 8640:2018, only class I bricks, in buildings of up to two storeys and with tie beams. The structural design should still be checked by an engineer.

What is the standard size of a lightweight brick? The common size in Table 1 is 600 x 200 mm, with thicknesses of 75, 100, 125 and 150 mm.