Rock wool sandwich panels and Autoclaved Lightweight Concrete (ALC) panels sit in the same wall-and-partition procurement category but solve different structural problems, and confusing the two regularly pushes the wrong spec onto a BOQ.
Rock wool panels are a rock wool-cored, factory-laminated composite with steel or aluminum facings, 45–200 mm thick, used as non-load-bearing cladding, partition, and cleanroom wall [S1][S4]. ALC panels are cement-bonded aerated concrete blocks (typically 600×300×75–200 mm), steam-cured in an autoclave, and used as load-bearing or non-load-bearing walling in residential and light-industrial buildings.
Material, Fire Rating, and Density Comparison
Rock wool cores carry Euroclass A1 (non-combustible) per UNI EN 13501-1 at densities around 120 kg/m³, with Cleanroom Italia's HPL-faced wall panel at 45 mm total thickness and a 4 mm HPL skin achieving B-s1-D0 [S1]. The facing alternatives (corrugated aluminum, A1) and aluminum side profiles sit on a 4 mm neutral silicone mastic joint, with overall panel thickness 45 mm in the cleanroom configuration [S1].
ALC panels are classified A1 non-combustible as a homogeneous material, with dry densities typically 400–650 kg/m³ depending on grade (B04–B06 class) and 28-day compressive strength usually quoted in the 3–6 MPa range. Standard dimensional spec (per Chinese GB 15762 and equivalent EN 12602): length 600 mm, width 300 mm, thickness 75/100/125/150/175/200 mm, with face tolerance ±3 mm, length tolerance +15/-3 mm, and thickness +5/-3 mm — values mirrored in the rock wool slab spec sheet published at 1200×600×50 mm with the same tolerance band [S10].
Decision Criteria: Where Each Panel Wins
For fire-rated industrial partitions, cold stores, cleanrooms, and prefabricated steel-structure envelopes, rock wool sandwich panels win on install speed (single-lift cladding, no wet trades), thermal conductivity (≈0.036–0.040 W/m·K for the core), and acoustic absorption (NRC 0.85–1.05 for 50 mm). The 120 kg/m³ high-density oriented-fiber rock wool variant from Cleanroom Italia is a deliberate upgrade from the 40–100 kg/m³ commodity rock wool slabs that Hangzhou Panovf and Foshan SAMZOON list as stock [S1][S3][S4].
For load-bearing walls, basements, fire compartments in residential mid-rise, and projects where the wall must take shelf loads, ALC panels win on compressive strength, single-material homogeneity (no facing delamination risk), and lower material cost per m². ALC's thermal conductivity (≈0.10–0.14 W/m·K) is roughly 3× higher than rock wool core, so a 200 mm ALC wall needs 100–150 mm of external insulation to match a 100 mm rock wool panel's R-value.
Cost, Lead Time, and Supply Chain
Rock wool panel pricing in mid-2026 on Made-in-China sits in the USD 8–18/m² FOB band for 50 mm steel-faced standard panels, with 100 mm A1 fire-rated variants quoted USD 14–28/m² depending on facing and density [S5][S8]. Foshan SAMZOON, Hebei Guangxing (line-builder since 1987), and Hangzhou Panovf are the three Chinese suppliers most consistently indexed on procurement platforms; Guangxing also sells turnkey sandwich-panel production lines with annual capacity 0.5–1.0 million m² [S3][S4][S9].
Lead time is 7–15 days ex-works for stock rock wool SKUs at SAMZOON and CMAX, versus 10–20 days for ALC depending on autoclave scheduling [S4][S5][S8].
Who It Is For — and Who Should Not Use Each
Specify a rock wool sandwich panel when the wall is a non-load-bearing envelope on a steel portal frame, a cleanroom partition (ISO 14644 class 5–8), a cold-store cladding, or a fire-rated service corridor needing 1–4 h FRR (tested per EN 1364-1, fire from either side). Rock wool is also the right call where acoustic absorption (NRC ≥0.90) and single-trade dry installation both matter. [S1]
Specify an ALC panel when the wall must carry vertical loads (shelf, mezzanine, upper-storey partition), when a homogeneous cementitious wall is needed for wet-area tiling, or when the project wants 100% inorganic A1 material with no facing-debonding risk over a 30+ year service life. ALC is the wrong call for high-R-value envelopes without added insulation, and rock wool sandwich panels are the wrong call anywhere a load path is expected.
Limitations, Failure Modes, and Common Spec Errors
Rock wool sandwich panels fail at the facing-to-core interface when water migrates through joints; specifiers must demand tongue-and-groove or shiplap edges with concealed fasteners, plus a vapor control layer on the warm side of cold-store walls. Core densities below 80 kg/m³ will slump under self-weight on vertical spans over 6 m — Cleanroom Italia's 120 kg/m³ spec exists specifically to avoid that [S1].
ALC panels crack at openings and at long unsupported lengths if reinforcement or a ring beam is omitted; they also need surface sealing against moisture in exterior applications because the cellular structure wicks water. A lightweight partition panel in the same wall family (e.g. AAC reinforced lintel panels) often gets used alongside ALC for door and window headers, and is a useful cross-reference when detailing penetrations.
Standards, Sourcing, and Verifiable Next Signals
Both materials are governed by separate code paths: rock wool sandwich panels test to EN 14509 (factory-made double skin metal faced insulating panels) and EN 13501-1 (fire), while ALC panels test to EN 12602 (AAC) and the parallel GB 15762 in the China market [S1][S10]. Sourcing side: Rockwool India Ltd. (Hyderabad) supplies the "Rockinsul" branded core, while the parent ROCKWOOL group brand was founded in 1937 and lists a USD 92.39 million registered capital entity in Guangdong [S2][S7].
Trackable near-term signals: new EN 14509-2024 third-party listings appearing on the NANDO database, and any revision of GB 15762 thickness-tolerance tables — both are the spec-side levers that will move rock wool vs ALC boundary cases on 2026 projects. For a broader sandwich-panel selection frame that includes ALC, see the Sandwich Panel vs ALC Panel spec-first selection map.