| Fixed Carbon-Steel Frame | Welded carbon-steel base with painted or powder-coated finish | 6–16 standard cylinders, depending on frame dimensions and cylinder diameter | Can be suitable when designed for the applicable transport, lifting, and cylinder-restraint requirements. Welding quality, load rating, tie-down points, and corrosion protection should be documented. | Usually includes steel pockets, chains, straps, or clamp bars. Forklift pockets and lifting lugs should be rated and clearly marked. | Regular inspection for corrosion, damaged welds, bent members, loose restraints, and coating failure. Damaged restraint hardware should be replaced promptly. | 8–15 years in normal industrial service; shorter in coastal, chemical, or high-humidity environments without refurbishment | US$900–1,800 | US$600–1,200 | US$1,500–3,000 | General industrial distribution, warehouse handling, and routine regional transport | Strong value |
| Hot-Dip Galvanized Steel Frame | Welded carbon-steel frame with zinc coating applied after fabrication | 6–16 standard cylinders | Provides improved corrosion resistance, but galvanizing does not replace requirements for structural design, securement, lifting-point verification, or periodic inspection. | Good compatibility with forklift pockets, lifting lugs, chains, and straps. Contact points should prevent cylinders from rubbing against sharp or abrasive surfaces. | Lower coating-maintenance burden than painted steel. Inspect cut edges, weld areas, impact damage, zinc loss, and fasteners for corrosion. | 10–20 years, depending on coating thickness, exposure, abrasion, and chemical environment | US$1,200–2,400 | US$450–900 | US$1,650–3,300 | Outdoor yards, humid areas, frequent loading cycles, and mixed-weather transport | Best balance for outdoor use |
| Stainless-Steel Frame | Fabricated stainless-steel structure with corrosion-resistant hardware | 6–12 standard cylinders | May be appropriate for corrosive or hygiene-sensitive environments, subject to the same structural, lifting, and cylinder-restraint requirements as other frames. Material selection should consider chemical compatibility. | Typically uses integrated pockets, straps, chains, or clamp systems. Galvanic corrosion should be considered where dissimilar metals contact each other. | Low coating maintenance, but welds, crevices, fasteners, and areas exposed to chlorides require inspection and cleaning. Surface contamination can still cause corrosion. | 15–25 years in suitable environments with proper cleaning and inspection | US$2,500–5,000 | US$400–1,000 | US$2,900–6,000 | Chemical processing, coastal facilities, clean environments, and applications where corrosion control is critical | Highest corrosion resistance |
| Aluminum Frame | Bolted or welded aluminum structure with corrosion-resistant fittings | 4–12 standard cylinders | Must be assessed for structural capacity, fatigue, impact resistance, lifting loads, and compatibility with the intended transport method. Aluminum can require larger sections to achieve equivalent stiffness to steel. | Lower tare weight improves manual positioning and vehicle payload efficiency. Cylinder restraints and lifting points must be designed to avoid local deformation. | Inspect for dents, cracks, fretting, loose fasteners, galvanic corrosion, and fatigue around joints. Repairs may require qualified aluminum fabrication. | 10–20 years when protected from severe impact and incompatible metal contact | US$1,800–3,800 | US$700–1,500 | US$2,500–5,300 | Payload-sensitive transport, frequent repositioning, and facilities requiring lighter handling equipment | Best for low tare weight |
| Modular Adjustable Steel Frame | Bolted or mechanically adjustable steel frame with interchangeable supports | 4–20 cylinders, subject to the approved configuration and rated load | Every configuration should retain the required load rating, center-of-gravity limits, restraint arrangement, and lifting instructions. Changeable components should be traceable and secured against incorrect assembly. | Flexible pockets, rails, straps, and dividers accommodate different cylinder sizes. More adjustment points require disciplined pre-use checks. | Inspect bolts, locking pins, adjustment slots, welds, restraints, and frame alignment. Maintain an inspection record for configuration changes and repairs. | 8–15 years, depending on adjustment frequency, impact exposure, and corrosion protection | US$1,600–3,500 | US$800–1,700 | US$2,400–5,200 | Mixed cylinder fleets, multiple depot configurations, and operations needing capacity flexibility | Most flexible option |
| Cost basis and selection notes: Indicative costs are generic market ranges in US dollars for the frame only and exclude cylinders, vehicle modifications, freight, taxes, certification testing, and local regulatory approval. Five-year total cost of ownership is calculated as purchase cost plus routine inspection, cleaning, corrosion control, restraint replacement, and minor repairs; it excludes major accident damage and downtime. Actual compliance requirements vary by jurisdiction, cylinder type, gas classification, transport mode, and lifting method. Always verify the applicable dangerous-goods transport rules, workplace-safety requirements, lifting standards, and manufacturer instructions before placing a frame into service. |