When a metro rail authority approves your louver for installation across seven stations, that approval is backed by documented, witnessed, third-party performance testing under an internationally recognised standard — not a manufacturer’s data sheet. For HVAC consultants, MEP contractors, and project engineers specifying ventilation louvers on metro rail or large-scale infrastructure projects in India, this distinction matters at every stage: tender evaluation, technical scrutiny, NABL certification submission, and defect liability.
In March 2026, KBG Group’s aluminium performance louver (Model KPL-80) completed a full weather performance test per BS EN 13030 at the NABL-accredited Eminent International Testing Centre (EITC), Hyderabad. The test was conducted for the Bangalore Metro Rail Corporation Limited (BMRCL) Phase-2, Reach-6 project — covering six underground stations (Cantonment, Pottery, Tannery Road, Venkateshpura, KG Halli, and Nagawara) and one elevated station (Kalena Agrahara). The louvers were supplied and installed by KBG Group, Nashik, for main contractor Anu Construction.
This article documents the test methodology, the complete results, and their practical implications for anyone specifying or procuring ventilation louvers for metro rail and critical infrastructure projects in India.
Project Overview and Test Details
The BMRCL Bangalore Metro Rail Project Phase-2, Reach-6 (Package-2) covers the balance architectural finishing works for six underground metro stations on the RT-03 and RT-04 corridors — Cantonment, Pottery, Tannery Road, Venkateshpura, KG Halli, and Nagawara — along with one elevated station at Kalena Agrahara. KBG Group was appointed as the louver contractor under main contractor Anu Construction, with BMRCL as the client authority.
The test was carried out at Eminent International Testing Centre Private Limited, Hyderabad (NABL Accreditation ULR No. TC1610626000000021F, TC-16106), operating under ISO/IEC 17025:2017. Final test report number EB37/01/Apr/2026/FR00 was issued on 1 April 2026. The test was witnessed and co-signed by representatives of KBG Group, Anu Construction, and BMRCL — providing three-party verification that the specimen tested was representative of the actual site supply.
The test standard applied was BS EN 13030, the European standard for weather louvres, covering water penetration resistance and pressure drop (discharge loss coefficient) measurement. All testing equipment — fans, flow meters, water spray nozzles, manometers, and measuring cylinders — were covered by valid calibration certificates at the time of testing.
Why BS EN 13030? Understanding the Standard for Metro Louver Testing
India’s metro rail projects routinely reference BS EN 13030 alongside IS 12433 and AMCA 500-L because BS EN 13030 provides the most structured and reproducible laboratory test procedure for two parameters that directly determine whether a ventilation louver performs safely in metro station environments: weather resistance under simulated wind-driven rain, and airflow resistance under varying fan operating conditions.
Underground metro station ventilation openings face a unique combination of demands. They must reject monsoon-intensity rainfall while ventilation fans are operating at face velocities of 1.5 to 3.5 m/s. They must impose the minimum possible pressure drop on the ventilation system to allow fan energy optimisation. And they must do both simultaneously. BS EN 13030 tests exactly this combined scenario in a single laboratory rig.
Water Penetration Test Methodology
The test specimen is mounted in an Aerodynamic Measurement Section (AMS). Simulated wind is applied at 13 m/s using a fan-driven wind section, and water is sprayed at 75 litres per hour per square metre to replicate monsoon-level rainfall. Air is simultaneously drawn through the louver at increasing face velocities — 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 m/s — to simulate ventilation fan operation. Water penetrating the louver at each step is collected and measured. The ratio of water rejected to water supplied gives the effectiveness percentage, which determines the BS EN 13030 water penetration class:
- Class A: Effectiveness 1.00 to 0.99 — maximum penetration 0.75 l/h/m². Applies at static or sheltered conditions.
- Class B: Effectiveness 0.989 to 0.950 — maximum penetration 3.75 l/h/m². Standard requirement for metro station ventilation openings.
- Class C: Effectiveness 0.949 to 0.80 — maximum penetration 15.00 l/h/m². For exposed high-wind or coastal locations.
- Class D: Effectiveness below 0.80 — not recommended for critical applications.
Pressure Drop Test Methodology
The louver is mounted on the opening of the AMS and static pressure is measured within the plenum chamber at increasing fan speeds. The discharge loss coefficient (CD) is calculated at each airflow step. A higher CD indicates lower louver resistance and better aerodynamic efficiency. BS EN 13030 classifies the result as follows:
- Class 1: CD 0.40 to 1.0 — high free area, low resistance, smallest fan size required.
- Class 2: CD 0.3 to 0.399 — moderate resistance.
- Class 3: CD 0.2 to 0.299 — high resistance, larger fan required.
- Class 4: CD 0.199 and below — very high resistance, significant system energy penalty.
Class 1 is the highest performance classification and represents the most aerodynamically efficient louver geometry for ventilation system design.
Test Specimen Specifications — KBG Group Model KPL-80
The specimen submitted for testing was a production-representative unit of the KPL-80 performance louver as supplied to the BMRCL project. All critical dimensions were independently verified and photographed by the testing laboratory before testing commenced.
- Type: Aluminium Performance Louver — Model KPL-80
- Face Area: 1,000 mm × 1,000 mm (1.0 m²)
- Core Area: 935 mm × 935 mm (0.87 m²)
- Frame Depth: 80 mm
- Blade Size: 115 mm
- Blade Spacing: 75 mm centre-to-centre
- Blade Angle: 45°
- Blade Orientation: Horizontal
- Number of Blades: 12 (11 free-air gaps)
- Free Area: 0.617 m² — 61.7% of total face area
- Surface Finish: Powder coated
A free area of 61.7% means that 61.7% of the total louver face area is open to airflow. For ventilation system designers, this directly determines the relationship between face velocity and pressure drop. Higher free area means lower face velocity for the same volume flow rate, reducing pressure drop and enabling fan energy optimisation. The 80 mm frame depth combined with 115 mm blades at 45° provides effective blade overlap for water rejection geometry under monsoon conditions.
Prior to testing, silicone sealant was applied at the bottom frame-to-blade joint and at frame corner joints on the backside — standard installation practice that was documented photographically in the test report annex. This represents real-world installed conditions, not idealised laboratory preparation.
Water Penetration Test Results
The water penetration test was conducted on 26 March 2025 with simulated wind at 13 m/s and simulated rainfall at 75 l/h/m² — conditions exceeding typical Indian monsoon exposure. Air was drawn through the louver at face velocities from 0 to 3.5 m/s. The complete results were as follows:
| Face Velocity (m/s) | Nominal Supply (l/h) | Water Penetrated (l/h) | Effectiveness | BS EN 13030 Class |
|---|---|---|---|---|
| 0.00 (static) | 99.81 | 0.44 | 99.34% | Class A |
| 0.50 | 99.31 | 0.69 | 98.98% | Class B ✓ |
| 1.00 | 98.46 | 0.99 | 98.54% | Class B ✓ |
| 1.50 | 97.40 | 1.34 | 98.05% | Class B ✓ |
| 2.00 | 96.23 | 1.74 | 97.50% | Class B ✓ |
| 2.50 | 95.10 | 1.95 | 97.23% | Class B ✓ |
| 3.00 | 94.12 | 2.37 | 96.67% | Class B ✓ |
| 3.50 | 93.43 | 2.56 | 96.43% | Class B ✓ |
The KPL-80 achieved Class A effectiveness at static conditions and Class B effectiveness across all ventilation operating velocities from 0.5 to 3.5 m/s. At the maximum test velocity of 3.5 m/s — which exceeds typical metro station design face velocities of 1.5 to 2.5 m/s — the louver rejected 96.43% of simulated rainfall. Only 2.56 l/h penetrated against the Class B maximum threshold of 3.75 l/h/m², providing a meaningful performance margin at real operating conditions.
Effectiveness values remained well above the Class B lower threshold of 95.0% at every tested velocity. The performance degradation from 0.5 m/s to 3.5 m/s is gradual and predictable, confirming that the blade geometry and angle provide consistent weather rejection across the full ventilation operating range — not only at low face velocities.
Pressure Drop Test Results
The pressure drop test was conducted on 27 March 2025. The discharge loss coefficient (CD) was measured across a range of face velocities from 1.92 to 13.46 m/s. Results were as follows:
| Face Velocity (m/s) | Test Flow (m³/s) | Louver Pressure (Pa) | Discharge Loss Coefficient (CD) |
|---|---|---|---|
| 1.92 | 0.550 | 1.0 | 0.464 |
| 3.84 | 1.100 | 3.9 | 0.470 |
| 5.76 | 1.651 | 8.9 | 0.466 |
| 7.69 | 2.204 | 15.7 | 0.469 |
| 9.61 | 2.754 | 24.4 | 0.470 |
| 11.53 | 3.304 | 34.7 | 0.473 |
| 13.46 | 3.857 | 46.8 | 0.475 |
| Mean Discharge Loss Coefficient | 0.469 — Class 1 | ||
The mean CD of 0.469 classifies the KPL-80 as BS EN 13030 Class 1 — the highest aerodynamic performance category. The coefficient remained essentially constant across the full test range (0.464 to 0.475), confirming stable, predictable performance across all fan operating points. For system designers, this stability allows accurate pressure drop calculation across the full variable-speed fan operating range without requiring separate data points for each condition.
At the practical design reference point of 3.84 m/s face velocity, the louver imposes only 3.9 Pa pressure drop. At a total system pressure of 24.4 Pa, the louver delivers 2.75 m³/s airflow through its 0.87 m² core area. This low-resistance characteristic allows ventilation system designers to size fans optimally, leaving system pressure budget available for ductwork efficiency and fan operating margins.
Why NABL Accreditation Matters for Government Tenders and Metro Projects
The test was conducted at Eminent International Testing Centre (EITC), Hyderabad — a laboratory accredited by NABL under ISO/IEC 17025:2017. NABL (National Accreditation Board for Testing and Calibration Laboratories) is India’s apex accreditation body under the Department for Promotion of Industry and Internal Trade (DPIIT), Government of India. NABL accreditation confirms that a laboratory’s test methods, equipment calibration, personnel competency, measurement traceability, and result reporting have been independently audited against international standards.
For project consultants and contractors, NABL accreditation has three specific implications. First, test results from NABL-accredited laboratories are accepted without additional scrutiny in all government tenders, BMRCL approval submissions, and CPWD or PWD procurement processes. Test reports from non-accredited labs are routinely rejected during technical evaluation even if the results themselves appear credible. Second, the Bangalore Metro test was witnessed and co-signed by representatives of BMRCL, Anu Construction, and KBG Group — providing multi-party verification that the specimen tested was representative of the actual supply and not a specially prepared laboratory sample. Third, the test report carries Unique Lab Report number TC1610626000000021F (TC-16106), which can be independently verified through the NABL portal at nabl-india.org, eliminating any possibility of document misrepresentation.
Contractors who specify KPL-80 in BMRCL, DMRC, MMRCL, or similar metro rail tenders can directly reference this test report number and NABL ULR during technical scrutiny. The three-party witness record eliminates procedural objections regarding sample representativeness.
Specification Writing Guide for Consultants
When preparing tender specifications for ventilation louvers on metro rail or large infrastructure projects, the performance clause should require certified third-party test data rather than manufacturer claims. The following clause is consistent with BMRCL Bangalore Metro Phase-2 standards and can be adapted for DMRC, MMRCL, NMRCL, airport terminal, or private infrastructure projects:
This clause excludes untested products and ensures the project authority receives verified, comparable performance data from all competing manufacturers. It references the key parameters — Class B water penetration, Class 1 pressure drop, 55% minimum free area — that align with BMRCL’s actual procurement basis for Bangalore Metro Phase-2.
Industry Applications: Where BS EN 13030 Class B Testing Is Required
The performance requirements demonstrated in this test apply across a broad range of infrastructure project types beyond metro rail.
Underground Metro Stations
Emergency ventilation shafts, OTE fan discharge openings, and platform tunnel ventilation intakes at underground metro stations carry the highest specification requirements of any building ventilation application in India. DMRC, BMRCL, MMRCL, and NMRCL all specify weather-tested louvers because ventilation failures in underground environments have direct life-safety implications. BS EN 13030 Class B is the minimum at all these authorities, with some projects requiring Class C for directly exposed street-level intake openings.
Elevated Metro Stations
Elevated stations face wind-driven rain at higher exposure levels than ground-floor openings. At 10 to 20 metres above grade, passive weather rejection in the absence of ventilation fan operation relies entirely on louver blade geometry. The KPL-80 demonstrated Class A effectiveness at zero face velocity, confirming that passive weather protection is maintained when fans are off.
Airport Terminal Mechanical Rooms
International airport terminal buildings governed by AAI and project-specific specifications routinely require BS EN 13030 or AMCA 500-L Class B compliance for AHU intake shafts, generator room ventilation, and mechanical room external openings. The same KPL-80 product and test certificate applies directly to these applications.
Industrial and Power Sector Projects
Power plants, large data centres, pharmaceutical manufacturing facilities, and chemical process plants in coastal or high-rainfall regions of India specify Class B or Class C tested louvers to protect generator rooms, switchgear buildings, and transformer bays from monsoon water ingress. The KPL-80 test data at 75 l/h/m² simulated rainfall covers the monsoon intensity levels encountered in West Coast, Northeast, and South Indian industrial locations.
About KBG Group’s Louver Solutions
KBG Group is an ISO 9001:2015 certified manufacturer of ventilation louvers, acoustic louvers, air distribution products, dampers, and industrial noise control systems, based in Nashik, Maharashtra. The BMRCL Bangalore Metro Phase-2, Reach-6 project represents the supply and installation of performance louvers across seven metro stations — a scope that required manufacturing precision, multi-station coordination, on-site installation capability, and the full technical documentation and third-party testing infrastructure demanded by a Tier 1 government rail client.
Our KPL-80 performance louver series is manufactured in-house at our CNC-equipped aluminium fabrication facility. All louvers are produced to project-specific dimensions, blade configurations, and surface finishes. Custom face sizes, frame depths, blade angles, alloy grades, and powder coat colours are available within standard infrastructure project lead times.
For projects requiring performance certification, we provide the current NABL-accredited BS EN 13030 test report (FR No. EB37/01/Apr/2026/FR00, NABL ULR TC1610626000000021F) as part of the technical submission package. Consultants and contractors can submit this report directly with their tender without commissioning separate testing.
KBG Group handles the complete project scope from engineering drawing preparation and manufacturing to pan-India logistics and on-site installation with our own erection teams. This single-vendor model eliminates the coordination delays and warranty disputes that occur when louver supply and installation are split between different contractors.
For acoustic louver requirements on the same project — where DG room ventilation, compressor rooms, or AHU intake openings require combined weather resistance and noise attenuation — our acoustic louver range is independently tested for insertion loss in addition to weather performance. Refer to our related technical article on acoustic louver specification for consultants for full specification guidance.
Conclusion
The BMRCL Bangalore Metro Phase-2 test results establish a clear, independently verified performance benchmark for KBG Group’s KPL-80 aluminium louver: BS EN 13030 Class B water penetration (96.43 to 99.34% effectiveness across the full 0 to 3.5 m/s face velocity range) and Class 1 discharge loss coefficient (mean CD 0.469), from a NABL-accredited laboratory, witnessed by BMRCL, Anu Construction, and KBG Group.
For consultants specifying ventilation louvers on metro rail, airport, industrial, or large commercial projects in India, this test report provides verified, current, NABL-certified performance data aligned with the standards referenced by India’s major metro rail authorities — BMRCL, DMRC, MMRCL, and NMRCL. The three-party witness record and NABL ULR reference eliminate documentation questions during tender technical scrutiny.
Contact KBG Group’s technical team to obtain the full test report (FR No. EB37/01/Apr/2026/FR00), engineering drawings for the KPL-80 series, BOQ specification clause wording, and project-specific quotation support.
Related Technical Articles
- Ventilation Louvers for Underground Metro Stations: IS 12433 Compliance, DMRC/MMRC Specs & Aluminium Alloy Selection Guide
- Aluminium Performance Louvers: AMCA Ratings Decoded for Indian Engineers + Specification Writing Guide
- Acoustic Louvers for Industrial & Commercial HVAC: Spec Writing Guide for Consultants
- Metro Station Facade Systems: Integrated Aluminium Cladding + Ventilation Solutions for India’s Urban Rail Projects