Software for the yard running double-wall tanks.

A double-wall tank is the unit a rental yard sends when a job needs to keep fuel, DEF, or waste fluid on site without a permanent tank farm and without a separate spill berm. The inner tank holds the product; the outer shell is built-in secondary containment, so a leak in the primary is caught rather than spilled on the ground. That is why these tanks travel to remote pads and outage sites where regulations demand containment and no infrastructure exists. They run differently from a machine: a tank is delivered, set on a level pad, and left to sit, earning every day it occupies the site. The work for the yard is not engine maintenance — it is the delivery, the dispensing kit, and the condition the tank comes back in. EquipFlow handles all of it on one record per unit.

Built inside Rental King, right now.

Rental King is a heavy-equipment rental yard in Odessa and Midland, TX. They run double-wall tanks, manlifts, forklifts, light towers, generators, compressors, and water trucks on MSA contracts through the Permian Basin — 24/7, oilfield pace. EquipFlow was designed and first deployed inside that yard. Every feature was tested against their live operation before it shipped. The product runs there today.

Tanks look simple to run and quietly leak money in two places. The first is standby: a tank that sits on a pad for weeks earns nothing if those days never make it onto the invoice, and standby is the entire rental for a unit built to sit still. The second is the return. A tank that comes back with product in the primary, water in the containment, or a contaminated load forces a cleaning and disposal cost the yard absorbs unless the return inspection catches it and charges it. Both problems come down to one discipline — every day billed, every return inspected, all against the same unit record. When dispatch, billing, and inspection read from one record, the standby days are on the invoice, the contamination is photographed at handover, and the bookkeeper closes the month without reconstructing where a tank sat or what it held.

Double-Wall Tank specs the rental record tracks.

Every number below is a sourced specification range. The render layer is the only path these values reach the page — they live on the unit record, not in a dispatcher's head.

Capacity (safe fill)

238-2388gal

Nominal (brim) capacity

251-1204gal

Footprint length

45-91in

Overall height

52in

Empty weight

1190-3726lb

Full (gross) weight

3178-14550lb

Secondary containment

110%

How EquipFlow handles double-wall tanks on the dispatch board.

A double-wall tank is set-and-forget once it lands, so the dispatch board treats it differently from a machine that moves all day. The hard part is the delivery itself and what rides with it. A tank dispatched without the pump, meter, nozzle, grounding strap, or fill fittings the customer expected is a return trip, so the dispatcher confirms the dispensing kit on the rental record before the truck leaves. Placement matters too: the tank needs a level pad and clearance for the fuel truck to reach the fill, so delivery notes carry the site contact and access detail. Because a tank that lands full versus empty is a different weight and a different truck, the dispatcher flags fill state at assignment. The board shows which tanks are out, which are queued for delivery, and which are due for pickup, on the same responsive screen at any hour.

Billing double-wall tanks — MSA, standby, and site-level tax.

A double-wall tank earns its keep by sitting, so the rental is almost pure standby — the unit bills for every day it occupies the customer's pad whether it dispensed a drop or not. That makes the standby line the spine of tank billing, and the dispatcher sets it on the rental without rebuilding the month at close. Most oilfield demand is MSA-contracted, so the negotiated rate lives as an override on the customer record per equipment class, and any tank rental created for that account applies it automatically. Delivery, pickup, and the dispensing add-ons ride the same invoice. Tax jurisdiction is set on the delivery-site record, so a tank that sat in one county carries that county's rate even if the customer's office is somewhere else. Invoices post to QuickBooks Online on close.

Maintenance on double-wall tanks.

Tank preventive maintenance is not engine-driven — there is no motor running up an hour meter the way a machine does. The clock here is throughput and time: the integrity rhythm tracks the manufacturer interval shown in the spec table, and the maintenance module schedules it against the unit's placement history rather than against engine hours. The real wear items are the dispensing side and the shell. Pumps, meters, hoses, nozzles, and seals get serviced and tested; vents and overfill protection get checked; the interstitial space between the primary and secondary walls gets verified clear of product or water. Coatings and welds get an eye for corrosion, because a tank that sat in standing water or carried waste fluid corrodes from the outside in. Work orders, parts, and inspection history live on the unit record, where a damage finding from a return becomes a repair ticket.

Double-Wall Tank return inspections.

The yard's control is the return inspection, run before the tank comes off rent. A double-wall tank carries inspection points a machine never will. The driver runs a mobile-web checklist on a phone — no app install — and confirms the primary tank is empty and clean of the product it held, that no waste or water is sitting in the secondary containment, and that the interstitial space shows no breach. Wrong-product contamination is the trap: a diesel tank returned with water in it, or a fuel tank that held something it should not have, is a cleaning bill the yard has to catch before off-rent. The checklist also covers the pump, meter, hose, nozzle, sight gauge, vents, and fittings, with required photos that cannot be skipped. The inspection ties to the rental record before the truck leaves, so a dispute over residue, contamination, or damage has photos and a timestamp behind it.

Common double-wall tank classes in the field.

The product, the same way it runs for double-wall tanks.

The sections below are the EquipFlow modules that matter most when running double-wall tanks — each links to the full feature detail.

Operator guides for running double-wall tanks.

Field-tested playbooks that go deeper on pricing, dispatch, billing, and maintenance for fleets like this.

• Dewatering Pump Rental Guide →
• Equipment Rental for Oilfield Operations →
• How to Bill for Equipment on Standby →
• Managing Recurring Rental Customers →

What you give up running double-wall tanks in EquipFlow.

EquipFlow is a web app, so the return inspection needs a signal to load. On a remote pad with no coverage, the driver cannot complete the mobile inspection at the customer site, so most yards run it at the yard on pickup — which means the photos of residue and containment land later than ideal. There is no built-in tank-monitoring integration today, so a level sensor or remote gauge on the tank is not pulled in automatically; fill state is recorded at delivery and return rather than streamed. And the billing logic is built around the MSA-and-standby model the oilfield runs on. A yard with throughput-based or per-gallon fuel billing should bring that to the demo so it can be scoped honestly.