Box-type prefabricated housing inspection

As an ISO/IEC 17025 accredited (CNAS) independent laboratory, we provide specialized inspection services for box‑type prefabricated housing (also known as modular containers, volumetric modular units, or prefab boxes) for manufacturers, construction companies, government housing programs, and disaster relief agencies in Argentina. Box‑type prefabricated housing consists of fully assembled, transportable modular units manufactured in a factory and then transported to the site for installation. They are widely used for worker camps in mining (lithium in Jujuy, Salta; copper in San Juan), oil & gas field accommodation (Neuquén, Comodoro Rivadavia), emergency housing after floods or earthquakes, temporary classrooms, and permanent affordable housing. Unlike traditional construction, modular units must withstand transportation vibration, lifting loads, stacking loads, and weather exposure during shipment. Our inspection covers structural integrity (frame, walls, roof, floor), electrical safety (wiring, panels, grounding), plumbing and water tightness, thermal insulation, air permeability, fire resistance of materials, and overall workmanship. We follow international building codes (IBC, IRC) adapted to Argentine regulations (CIRSOC, IRAM). Results help manufacturers certify their products, secure government approvals, and provide safe, durable housing for Argentina’s diverse climates – from the Andean highlands to the humid Pampas.

Types of Box‑Type Prefabricated Housing Units We Inspect

Single‑module units (one container sized 6m × 2.4m × 2.6m or custom dimensions)
Multi‑module combinations (side‑by‑side, stacked up to 3 stories with structural calculations)
Open‑plan modules (without internal partition walls) for commercial use (offices, shops)
Fully finished housing units (with kitchen, bathroom, bedrooms, electrical, plumbing, finishes)
Basic shell units (envelope only) for on‑site finishing
Emergency shelter units (rapid deployment, light frame, simplified finishes)
Cold‑climate insulated units (extra insulation, double glazing, thermal break) for Patagonia
Hot‑climate ventilated units (shading devices, reflective roof coating) for northern provinces
Custom designs for mining camps, construction sites, healthcare facilities, schools
Used refurbished containers being re‑purposed for housing

Structural Inspection – Frame, Walls, Roof and Floor

The structural integrity of a box‑type prefab unit ensures safety under dead loads (self weight), live loads (occupants, furniture), wind loads, and snow loads (where applicable). It also must survive lifting from the factory, transport on trucks, and stacking during storage.

Frame inspection (steel or light gauge steel, wood, composite) – We verify the dimensions of the main beams (corner posts, top and bottom rails, cross members) against the engineering drawing. Corner fitting holes (for stacking and lifting) must be correctly aligned and reinforced. Weld quality is inspected visually and by dye penetrant (for steel frames). Bolted connections are torque‑checked. Corrosion protection (galvanizing, painting) is evaluated.
Wall panel construction – For sandwich panel walls (e.g., EPS foam between steel sheets), we check panel thickness, core density (kg/m³), and adhesion between the skins. For timber frame walls, we inspect stud spacing, nailing pattern, sheathing attachment, and bracing. Any bulging, bowing, or separation is recorded.
Roof and floor load testing (simulated live load) – We apply a uniform distributed load (e.g., 200 kg/m² for floor, 150 kg/m² for roof) using water bags or calibrated weights. Deflection is measured at mid‑span and corners. After unloading, permanent deformation is measured. Acceptance criteria: elastic deflection ≤ L/250, no permanent deformation, no cracking of finishes.
Lifting and transport simulation test (optional) – The unit is lifted by its four lifting points with a crane; the lifting angle is measured. We inspect for permanent deformation, cracking of wall panels, or door/window misalignment. For transport, we simulate vibration on a shaker table (3‑axis, 5–50 Hz, 2 hours) to detect loose connections, squeaking, or fatigue failure.
Stacking (vertical load) test – For multi‑story applications, we place one unit on top of another (or apply a hydraulic ram to simulate the weight of additional stories). The lower unit is inspected for column buckling, floor deflection, and wall panel damage. The stacking load is calculated based on the number of intended stories plus a safety factor (typically 1.5).

Electrical System Inspection – Safety and Functionality

Electrical installations in prefab housing must comply with Argentine regulations (AEA 90364, IRAM standards) and be safe for the end user.

Wiring inspection – Type of cable (e.g., IRAM 2183, thermoplastic insulated, copper), cross‑section (1.5 mm² for lighting, 2.5 mm² for power outlets, 4 mm² for water heaters, etc.), color coding (green/yellow for ground, blue for neutral, brown/black for live). Routing must be away from sharp edges and protected by conduit.
Grounding (earthing) system – Resistance of the ground rod (or ground connection) measured with a ground resistance tester. Acceptable limit: ≤ 10 Ω for residential units. Continuity between all exposed metal parts (frame, panel skins, appliances) and the grounding busbar is checked with a low‑resistance ohmmeter (≤ 0.1 Ω).
Polarity and insulation resistance – Using an insulation tester (megger), we apply 500 V DC between live conductors and ground. Minimum insulation resistance: 1 MΩ. Polarity is checked to ensure that switches are on the live line and sockets are wired correctly (left neutral, right live, top ground).
Circuit breaker and protective device verification – Ratings of circuit breakers (thermal‑magnetic) and residual current devices (RCDs) are verified against the design. RCD trip time is measured (should be ≤ 0.04 s at 30 mA). Overload trip simulation (secondary test) is performed using a portable tester.
Functional test of lighting, fans, outlets – All lights are switched on/off; all power outlets are tested with a plug‑in tester. For pre‑installed appliances (water heater, air conditioner, stove fan), we perform a power‑up test (if client authorizes and utility connection is available).
Socket outlet pull‑out force – A calibrated gauge measures the force required to remove a plug from each outlet; loose sockets (force < 5 N) are recorded as defects.

Plumbing and Water Tightness Inspection

Leaks in plumbing can cause structural damage and health hazards. Our inspection includes both pressurized water lines and drainage systems.

Water supply lines (pressure test) – The system is filled with water, air is purged, and pressure is raised to 1.5 times the working pressure (minimum 0.6 MPa or 6 bar). The pressure is held for 1 hour; a drop > 0.05 MPa indicates leakage. Joints, valves, and fittings are inspected for visible weeping.
Drainage and waste pipe test (water tightness) – The drainage stack is sealed at the bottom and filled with water to the highest trap. A water column of 1 m height (or equivalent pressure) is maintained for 15 minutes. No water level drop indicates no leakage.
Water heater and fixture functional test – The water heater (if provided) is tested for gas or electrical safety (client‑supplied utility), flow rate, and hot water delivery temperature.
Leakage test of wet areas (shower, bathroom floor) – The bathroom floor is flooded with 20 mm of water (contained by a dam) for 24 hours. Any water seepage to the floor below or to the exterior indicates failure of waterproofing membrane.
Tap and valve operation – All taps (faucets) are opened/closed, checked for smooth operation and absence of cross‑connection (hot/cold reversal).

Thermal Insulation and Air Permeability (Energy Efficiency)

For prefab housing to be comfortable in Argentina’s varied climates, proper insulation and air tightness are essential.

Thermal insulation thickness and continuity – Using a non‑invasive thermal imaging camera (or core sampling when allowed), we verify that insulation (fiberglass, EPS, polyurethane foam) is continuous, without voids or gaps, and that the thickness meets the design (typically 50–150 mm depending on the region). For sandwich panels, we measure the core thickness and check for thermal bridging at joints.
In‑situ thermal transmittance (U‑value) measurement (optional) – Using heat flow meters and temperature sensors on the interior and exterior, we measure the actual U‑value (W/m²·K). This is compared to IRAM 11601 requirements for energy efficiency. A U‑value of ≤ 0.5 W/m²·K is typical for Patagonia; ≤ 1.0 W/m²·K for Buenos Aires and central regions.
Air permeability (blower door test) – The unit is sealed, a calibrated fan is installed in a door, and a pressure difference of 50 Pa (positive or negative) is created. The air flow rate at 50 Pa (Q₅₀ in m³/h) is measured. The air change rate n₅₀ = Q₅₀ / volume (h⁻¹). Acceptable n₅₀ for prefab housing: ≤ 10 h⁻¹ for standard construction; ≤ 5 h⁻¹ for energy‑efficient units. Leaks are located using smoke pencils or thermal imaging.
Condensation risk assessment – Using measured U‑value and air permeability, we compute the temperature factor (fᵣₛᵢ) to check if internal surface condensation is likely. If fᵣₛᵢ < 0.7 (at outdoor design temperature), additional insulation or improved air tightness is recommended.

Fire Safety and Material Flammability

Prefab housing units must meet fire safety requirements for egress, flame spread, and smoke development.

Flammability rating of wall and ceiling linings – Samples of the interior finish materials (e.g., PVC ceiling, vinyl wall covering, plywood, melamine board) are tested (if separately supplied) for flame spread index (FSI) and smoke developed index (SDI). For quick assessment, we use a small‑scale flame test on representative cut‑outs (if allowed by the client).
Egress pathway inspection – Doors must open outward in the direction of escape. Width and height of doors and corridors are measured. Minimum clear width for a bedroom door: 0.8 m; for main entrance: 0.9 m. Smoke detectors (if installed) are tested for alarm sound level (≥ 85 dB at 1 m).
Fire resistance of structural elements (if required) – For multi‑stacked units (2 or 3 stories), we require a fire rating test (from an accredited external laboratory) for the floor‑ceiling assembly (minimum 60 minutes fire separation). We verify that the fire‑rated assembly has been properly sealed at penetrations (pipes, conduits).

Workmanship and Finishing Inspection

Visual and dimensional checks ensure that the unit is fit for occupancy and meets client’s aesthetic requirements.

Dimensions and squareness – Length, width, height are measured and compared to the approved drawings. Diagonal differences (to check squareness) should be ≤ 10 mm for a 6m module.
Wall and ceiling flatness – A 2 m straightedge is placed against wall and ceiling surfaces; gaps > 5 mm are recorded as uneven.
Door and window operation – Each door is opened/closed; any sticking, scraping, or hardware looseness is noted. Windows are operated and checked for air leakage (by feeling for drafts).
Floor covering (vinyl, laminate, ceramic tile) – Flatness, gaps at joints, lippage between tiles, and any loose areas are inspected. Impact sound transmission (footsteps) is assessed subjectively.
Paint and surface finishes – Evenness of paint, blisters, sags, and discoloration. For exterior cladding, we check for scratches, dents, or corrosion spots.
Hardware and accessories – Locks, handles, towel bars, curtain rods are checked for secure attachment.

Inspection Report and Deliverables

Each box‑type prefabricated housing inspection report includes the following information:

Unit identification (manufacturer, model, serial number, dimensions, intended use)
Structural findings: frame dimensions, weld quality, lifting point verification, deflection under load, stacking capacity
Electrical results: insulation resistance (MΩ), ground continuity (Ω), polarity, RCD trip time (ms), functionality of outlets and lighting
Plumbing results: pressure test drop (bar), water tightness of drainage, shower pan leak test (pass/fail)
Thermal results: insulation thickness (mm), U‑value (W/m²·K) if measured, air permeability n₅₀ (h⁻¹), condensation risk
Fire safety: flame spread rating (if tested), egress dimensions, smoke detector test (if present)
Workmanship: list of defects (cracks, unevenness, misaligned doors, paint defects) with photographs
Overall conclusion: “Conforming” (all criteria passed), “Conforming with remarks” (minor defects that do not affect safety), or “Non‑conforming” (major defects requiring rework)
Comparison with client‑supplied acceptance criteria (if provided)
Raw data (load‑deflection curves, insulation resistance logs, thermograms) archived for 10 years

No statement of compliance with any external standard or regulation is made unless the client has provided specific acceptance criteria in writing. The report is intended for factory release, site acceptance, and warranty purposes.

Applications in Argentina’s Prefabricated Housing Industry

Mining worker camps (Lithium, San Juan copper, Santa Cruz gold): Inspection of modular housing for harsh conditions (strong winds, seismic risk, transport on unpaved roads).
Oil and gas field accommodation (Vaca Muerta, Neuquén): Off‑site inspection before shipment to remote locations, including electrical explosion‑proof requirements for hazardous areas (when applicable).
Emergency housing programs: Rapid inspection for quality assurance of government‑procured units after floods or earthquakes.
School and health clinic modules: Inspection of prefab boxes for thermal and acoustic comfort, accessibility, and electrical safety.
Export quality verification: Units destined for neighboring countries (Chile, Bolivia, Uruguay) are inspected to meet cross‑border transport and local building code requirements.