China sourcing desk: supplier evidence and comparable quotations for modular building projects.
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Modular and portable buildings
A relocatable building (RB) for a two-year site office and a permanent modular construction (PMC) clinic do not share a foundation interface or a fire strategy. Start with use, climate and how fast the first unit must stand.
Prefabricated houses
For light-gauge steel (LGS) houses, ask each supplier for a recorded stud layout before fabrication. Span and connection details belong to the project engineer. Panelized transport density is higher than a finished volumetric box, and the site crew closes more joints.
Steel buildings
Pre-engineered building (PEB) offers need a stated clear span and design basis. Supplier proposals should name the steel grade, such as Q355 or S355 where applicable, only after local wind, snow and seismic criteria are confirmed.
Primary line: modular and portable buildings. Adjacent systems stay on the same inquiry form so a mixed camp does not split across vendors by accident.
Ask each supplier for the external dimensions and wall-panel build-up of the quoted model. Calculate the loading plan per order from package dimensions and lifting limits. Confirm how the completed module is secured for its route.
MEP preinstallation can stop at conduit and sleeves, or include sanitary pods. The factory and site split is listed line by line so a missing water heater is not discovered after the crane leaves.
Inquire on this systemBolted knock-down frames raise packing density. Torque marks and seam tapes belong in the first-unit record.
Request a packing noteDouble-wing modules cut transport volume and add hinge hardware that must be cycled before shipment.
Ask about deployment speedPanelized cold-formed steel (CFS) suits longer occupancy when the local energy code sets the U-value.
Compare with volumetricGalvanized coating mass such as Z275 is a specification, not a corrosion warranty for cut edges.
Send a coating questionPortal frames, purlin and girt spacing, and moment connections follow the frozen load sheet.
Share a span sketchClear span and door openings drive frame weight more than wall colour or cladding brand.
Describe the crane or doorDormitory, dining and ablution blocks need a fire strategy for the whole linked wall, not one panel coupon.
Outline camp headcountThese five checkpoints describe the procurement workflow, not factory capacity or a promise of project approval.
The four cards are comparison exercises showing how a buyer brief changes supplier questions. They are not completed projects or delivery claims.
Illustrative brief: 24 site offices in a coastal wind zone. We would ask each supplier for the design wind basis, bolted-frame details, lifting-point calculation and a clear split between factory electrical work and site HVAC connections. A site engineer must confirm the foundation interface.
Illustrative brief: 12 classrooms with a 1.5 kN/m² ground snow criterion. Supplier offers should separate roof design loads, PIR panel data, floor-rim thermal bridges and the fire evidence for the complete wall assembly. Door and module-joint evidence need their own review lines.
Illustrative brief: eight clinic modules in a seismic region. We would compare hold-down calculations, two-storey drift criteria and mineral-wool panel evidence, then ask where sanitary-pod work ends and local medical-gas scope begins. Any numerical seismic basis must come from the local designer.
Illustrative brief: 36 camp dormitory modules delivered against staged foundations. We would request a load sequence, lifting plan, spare-parts list and packing photographs. A building module should not be described as an ISO CSC freight container without the relevant evidence.
Offices, induction rooms and stores. Wind exposure is usually the first number.
Linked classrooms. Acoustic joints and a snow or cyclone note travel together.
Wider corridors and medical MEP limits. Factory scope stops where gases begin.
Dormitory plus dining. Fire strategy is for the linked building, not one coupon.
Short leases. Relocatable classification still needs the local permit path.
Portal frames when clear span and cranes exceed a module box.
No. Temporary classification and permanent compliance are different permit conversations. A module that can be lifted still needs the wind, fire, energy and accessibility rules of the country where people occupy it. Our sourcing desk will not promise an IBC, Eurocode or NCC approval before the authority and the site are named.
EPS sandwich panel cores are lighter and usually cheaper. PIR sandwich panel cores improve the U-value at the same thickness. Rock wool adds mass and a stronger fire conversation. None of those sentences is a system fire rating. Doors, windows and the module joint need their own evidence.
If a supplier presents ISO 9001, ISO 14001 or ISO 45001, we verify the certificate scope and current status. These management systems do not certify a frame, a weld or a wall. Structural work follows the project standard, which might be AWS D1.1 language or a European execution class when that market applies.
A welded volumetric module keeps more work in the factory and consumes more ship space. A bolted frame packs tighter and moves the accuracy check to site torque and seam alignment. The selector page puts both options next to climate and programme, because the cheaper freight choice can add days on the slab.
Use, quantity, country, plan size, storeys, design wind speed, ground snow load, seismic design category or PGA, interior scope, destination port and the month the first module must be weather-tight. Missing loads are a pause, not a guessed default.
A panel tested to EN 14509 describes the panel product. The occupied building also has corners, floors and openings. If a 60-minute fire resistance rating is required, the submittal has to name the assembly that was tested, including joints.
A useful reply names the system family, the factory versus site split, and the documents still missing. It does not promise a permit.
Start with the brief