This guide concerns an RFQ for an engineering service, not an enquiry to buy gas. A tube trailer, T50 portable tank and T75 cryogenic portable tank have different pressure systems, fittings, service histories and inspection contexts. The designation alone does not define a universal test plan. SG Trading therefore develops the service scope from the identified asset, its documentation, operating condition, location and the required deliverable.
1. Identify the exact asset before discussing methods
Provide the owner, operator, manufacturer, serial or asset number, plate photographs, container or chassis identification and the available certificate set. State whether the equipment is a tube trailer, a portable tank associated with a T50 instruction, a cryogenic portable tank associated with T75, or another pressure assembly. The data plate and approved records are more reliable than a commercial nickname.
Include the design code or approval basis shown in the records, year of manufacture, last periodic inspection or test, next due date and any repair or modification history. Exact statutory applicability depends on the equipment, jurisdiction, route and competent or authorized body. An initial records review helps prevent an unsuitable field scope.
2. Describe product history and current condition
Name the current and previous medium, normal operating pressure and temperature, whether the asset is loaded, empty, depressurized, purged or cleaned, and whether safe isolation can be arranged. Product history matters because residual gas, contamination, oxygen deficiency, flammability, toxicity and cryogenic conditions can change access and test preparation.
Report the observed concern without diagnosing it prematurely. Useful evidence includes pressure loss, alarm history, odour reports where relevant, frost pattern, damaged fittings, impact, corrosion, vibration, unusual noise or a failed operational check. Add dated photographs and indicate whether the equipment can be removed from service.
3. Separate leak search, site audit and periodic inspection
A leak search aims to locate or narrow a suspected loss of containment under agreed safe conditions. A site audit reviews equipment interfaces, access, operating practice, records and service readiness. Periodic inspection planning addresses due dates, preparation, test location, authorized parties and the records needed to return an asset to service. These are related but distinct assignments.
Possible activities can include records review, visual examination, acoustic assessment, leak testing and selected non-destructive testing. No single method is automatically suitable for every tube trailer, T50 or T75 asset. The final method, preparation, acceptance criteria and need for statutory witnessing are agreed for the identified equipment and applicable framework.
4. Define the site and access conditions
State the country, city, facility type and whether the work is planned at an operating site, depot, port, workshop or customer premises. Describe working height, safe access, lighting, weather exposure, exclusion-zone possibilities, utilities, lifting support, scaffolding and permit-to-work requirements. For a road unit, confirm whether the tractor and chassis will remain available. For a tank container, identify any frame damage or access obstruction.
The RFQ should explain who can isolate, depressurize, purge, clean and release the equipment. Also state which site induction, personal protective equipment, gas detection, safety supervision and local documentation are mandatory. This information affects both the technical scope and the time needed on site.
5. State the required decision and deliverable
An inspection request becomes useful when the customer defines what the report must support. Examples include locating a leak, documenting visible condition, planning a periodic inspection, establishing a repair scope, evaluating a loading or unloading interface, or recording observations before handover. A generic request to “check the container” does not provide an acceptance basis.
Agree whether the deliverable should contain photographs, marked locations, instrument readings, observations, recommended actions, repair priorities or a service record. An engineering report is not automatically a statutory certificate. Where formal certification or witnessing is required, that requirement and the responsible authorized organization must be identified before work begins.
6. Prepare a service RFQ that can be scoped
Asset type and ID, plate and certificates, owner, current and previous medium, operating status, pressure and temperature, last inspection, observed concern, site, access, isolation and cleaning availability, required decision, deliverable and timing.
Attach legible records and representative photographs through the structured RFQ. Select the engineering or service path rather than a product-supply request. SG Trading can then clarify whether the requirement is a site audit, leak search, periodic inspection plan or a combined assignment.
7. Connect inspection with safe package operation
Inspection findings often affect package preparation, filling interfaces, transport readiness and return planning. The packaging overview explains the role of package type, valves and pressure, while the quality section describes controlled records and acceptance evidence. The broader engineering capability page covers inspection and on-site support.
For cryogenic logistics, see the guide to specifying liquid helium and tank return. Each final scope remains asset-specific: photographs illustrate processes, but they do not establish a method, tolerance, certification or responsibility for a particular unit.