An installation is a small city with a heavier fleet, a stricter fence, and a submittal register. Wash racks, motor pool hardstand, POV lots, barracks and family housing sit inside one boundary and drain nothing alike. Here is how we read the water zone by zone, where Class E and F genuinely belong, and where our scope stops and another trade's begins.
One fence line, twenty different drainage problems
Walk an installation with a drainage eye and it stops looking like a facility. Inside one boundary sit hangar aprons and a fuel farm, a central vehicle wash facility, a motor pool with acres of hardstand, a commissary dock, a dining facility, barracks, several hundred privatized family housing units on their own cul-de-sacs, ball fields and an outdoor pool, a headquarters with a flag circle, and an access control point where two lanes stack up every weekday morning. A maneuver post runs to tens of thousands of acres; a Guard readiness center might be forty acres and a drill hall. Both are on this page.
What makes installation drainage its own discipline is not that any single piece is exotic. It is that all of it shares a property line, a public works shop, one stormwater permit and one criteria system while asking for wildly different hardware. The pavement outside the barracks wants what a well-built apartment complex wants. The pavement three hundred yards away has to survive a seventy-ton tracked vehicle pivoting on it. Treating those as one job — which is what happens when a drain gets picked once and repeated across a site plan — is the most expensive mistake we see on base work.
The second thing is procurement. Nothing here is a walk-in purchase. It is a spec section, a submittal, a load-class citation, an or-equal request, an origin question, and a delivery to a gate that needs an appointment and possibly an escort. On a federal job the buying is half the problem, so we cover that too.
The drainage needs an installation actually has — and who fills each one
Every decision comes back to one question asked in a specific place: is this water moving across a surface, or is it already in the ground? The answer sorts the problem, and it sorts what we sell from what we do not.
Surface water on pavement — our layer. Aprons, hardstand, motor pool aisles, wash pads, POV lots, gate plazas and sidewalks shed essentially everything that lands on them. That water leaves as sheet flow, gathers into a concentrated ribbon at the low edge, and goes wherever grade sends it: under a shop door, into a containment area, or across a soft shoulder it proceeds to erode. Two devices catch it — a channel or trench drain laid across the path of the flow, and a catch basin set where water already collects at a point.
Water already in the ground — a site contractor's layer. Under PT fields and parade grounds, along soggy training-area shoulders, behind a retaining wall at a depressed wash rack, and as edge drain beneath heavy pavement base, installations legitimately use subsurface systems. A french drain is perforated pipe, commonly 4″ to 6″, bedded in washed stone and wrapped in geotextile, cut in to intercept groundwater rather than catch anything off a surface. It is a real answer to a real problem and you will find it on every post in the inventory. It is also excavation work priced by the linear foot, and we do not sell it — nothing in our catalog is a french drain and we will not call one that. When the complaint is a saturated field, the honest answer is: hire a site contractor for the subsurface, and let us handle the surface collection that keeps water from concentrating there to begin with.
Water that must be contained or treated — by others. At a wash rack, fuel point, POL yard, deicing pad or hazardous-material area, catching the water is only the first act. Oil-water separators, grit and sand interceptors, reclaim skids, lift stations, pumps and any form of treatment sit downstream of us, engineered and permitted by others. We say so early on every base call, because the interceptor's inlet invert usually dictates how deep the trench may be — settle that elevation before anyone picks a channel. Same with the site-civil package: culverts, headwalls, RCP mains, curb inlets and detention belong to the civil design. None of it changes what catches water at the surface.
How the water moves, and how to prove your system can carry it
The number that matters is gallons per minute arriving at a point, and it is knowable before anything is selected. Start with tributary area, which on a base is almost never just the pavement in front of you: a hangar apron collects the roof draining onto it, a motor pool aisle collects the two rows of hardstand pitched into it, a lot below a hillside collects the hillside. As a working figure, 1,000 square feet of impervious surface sheds about 623 gallons per inch of rainfall — a 200′ × 120′ apron gives up roughly 15,000 gallons in a one-inch storm. Run your real area and intensity through the Runoff Calculator, and read Sizing for Storms: Estimating Runoff for the method, so you can defend the number in a design review.
Then add the water that has nothing to do with weather. Wash racks, hangar washdown, fire-suppression test discharges and hydrant flushing arrive on a human schedule and can dwarf the storm. Hand wands run roughly 4–6 gpm each; a tactical rinse arch runs far higher. Sum every nozzle that can physically run at once, not the number that usually do.
Then check the outlet, because the outlet is the bottleneck. This is the failure we get called about most: a beautiful 12″ channel tied to a 4″ outlet, backing up in the first real storm while everyone blames the grate. Flowing full at 1% slope, 6″ pipe carries roughly 250 gpm, 8″ about 540 gpm and 10″ about 985 gpm. If your peak exceeds that, no channel on earth fixes it — you need a bigger outlet, more outlets, or storage. Pitch pavement to the drain at 1/8″–1/4″ per foot, keep at least 2 feet per second moving through the channel so grit stays in suspension rather than packing into the invert, and give every long run a point a vac truck can reach. On northern-tier posts, size the low point for the snow pile, not just the storm: a whole POV lot's plowed accumulation melts into one corner over a warm week, and that corner needs storage below the outlet invert, not a 9″ box.
Reading load class off the heaviest thing that turns on it
Channel and grate ratings follow EN 1433, which loads a grate to failure and reports the result as a class in kilonewtons. The trap on installation work is reading class off the average vehicle. Spec the worst case, and watch anything that stops, idles and steers on the grate line — a slow pivot puts far more punishment into a frame than the same vehicle at speed.
EN 1433 class → where it belongs on an installation
Class
Test load
Typical base pavement
A 15
15 kN · ~3,400 lb
Pedestrian only — memorial walks, courtyards, PT paths. Never where a vehicle can wander.
B 125
125 kN · ~28,000 lb
Family housing driveways, walkways with occasional light vehicles, MWR pool decks.
C 250
250 kN · ~56,000 lb
POV lot drive aisles, curb lines, admin and barracks access drives, gate walkways.
D 400
400 kN · ~90,000 lb
Floor for anything a military truck uses: motor pool aisles, wash aprons, ACP lanes, dock aprons.
E 600
600 kN · ~135,000 lb
Tactical hardstand, wash racks taking tracked vehicles or HET/PLS rigs, container and MHE yards.
F 900
900 kN · ~202,000 lb
Where the designer of record marks the heaviest pavement on post. Ask; do not assume.
Two honest caveats. The American shorthand and the European classes come from different test frameworks: the trade heuristic reads H-20 as a 16,000-lb wheel load and HS-25 as 20,000 lb, loosely mapped onto Class D and E, but that is a rule of thumb for conversation, not a standards equivalence, and the design of record governs. And every published class assumes full concrete encasement per the manufacturer's instructions, inside the pavement section your engineer designed — a Class F grate in a bad pour is not a Class F drain. Full matrix in our Load Recommendation Guide.
Tracked vehicles deserve their own sentence. A main battle tank runs about seventy tons combat-loaded but spreads it across two tracks, so ground pressure is modest; the damage comes from steel track shoes gouging edge rails and pivot steers shearing a frame sideways. Keep grate lines out of turning areas where geometry allows, run them straight across the direction of travel, and where a track must cross, specify ductile iron with a heavy edge rail and boltdown fixing rather than a lighter grate carrying the same class number. More on that punishment: heavy traffic drainage.
Where drains actually go, zone by zone
Central vehicle wash facility & unit wash racks
The CVWF is the most demanding drainage on most installations, and UFC 4-214-03 is the criteria document governing central vehicle wash facilities. The problem is a scheduled flood carrying mud, sand, POL residue and detergent onto one slab, with tracked and heavy wheeled vehicles stopping directly on the grate line. We spec Class E as the working default, a sloped channel rather than a neutral run so grit keeps moving, sediment buckets in the line, and a basin with real storage below the outlet at the end. Surface capture is the whole of our scope — separator, interceptor and reclaim equipment are downstream, by others. Unit racks at a motor pool are the same problem smaller; fleet and truck wash drainage works the wash-water arithmetic in detail.
Motor pool hardstand, maintenance bays & POL
Motor pools are acres of pavement pitched to a few lines, and everything crossing them arrives caked in whatever the training area is made of. Sediment management is therefore not optional: silt buckets, generous basin sumps, and a cleanout interval written onto a work order — monthly on a maneuver post, quarterly on a Guard site. Inside maintenance bays, a trench across the door line intercepts what runs off the vehicle before it reaches the shop floor. At fuel points and POL yards, containment is engineered by others; we supply what the design calls for at the surface and make no claim about what happens to hydrocarbons after collection.
Airfield, hangar aprons & deicing pads
Airfield pavement is governed by airfield criteria and aircraft wheel loads that sit outside the road-class conversation entirely, so nothing here gets picked off a residential chart. What we contribute is the apron, hangar door line, wash ramp and GSE road collection: heavy channel at the door threshold so washdown and driven rain do not run inside, and locked, boltdown grates near movement areas, because a loose grate on an airfield is FOD. Where deicing fluid is collected, containment and whatever happens to the glycol is by others. The flight line itself is covered properly on our airport drainage page.
Access control points, gates & POV lots
Gates concentrate three things at once: traffic stacked at idle, pedestrian routes that must stay accessible, and a security plan that cares about openings. Standoff requirements push POV parking away from occupied buildings, so lots sit at the perimeter and collection runs long — settle the outlet before the lot layout hardens. Grate selection at an ACP is a heel-safety and security question together: on an accessible route, openings must not pass a 1/2″ sphere, and elongated openings run perpendicular to the dominant direction of travel. Any structure crossing a controlled-area boundary gets barred or grated under the physical security plan — a design decision by others, not a catalog item.
Barracks, privatized family housing & admin
This is the most ordinary drainage on the installation and where the most money gets wasted, because heavy commercial hardware gets copied into a residential neighborhood out of habit. Housing streets, unit driveways, garage thresholds, patios and downspout discharges want what a well-built subdivision wants, and privatized housing partners run their portfolios much the way a management company runs a community — our HOA and property management page speaks that language. This zone is orderable straight from the catalog; there is no reason to quote it.
MWR, dining facilities & the exterior of everything else
Pool and splash decks, ball fields, the commissary dock, the dumpster and grease-container pads behind the DFAC are exterior collection problems with good, buyable answers. Base pool decks want a purpose-built product: Stegmeier Frontier and Flowmaster give a flush, barefoot-safe perimeter line, and putting a vehicular channel around a pool deck buys nothing but cost and a worse walking surface. One honest boundary: the kitchen floor inside a dining facility is hygienic interior drainage — engineered sanitary stainless, crevice-free construction, the whole regulated world of it — and we do not sell that. We serve the exterior and general-duty zone: dock apron, grease-container pad, delivery route, walkways.
What we would spec on a base, and why
Every pick assumes you have already run the tributary area and confirmed the outlet can carry the number. Capacity first, then hardware.
Best for tactical pavement and the wash rack — ACO PowerDrain
S100K · S200K · S300K · Class E territory · quote-only
The flagship for the heavy half of an installation, and what we put in front of a contractor speccing a CVWF, a tactical hardstand line, a container yard or an MHE apron. Take S100K at 4″ where width is constrained, S200K at 8″ as the sensible default for a wash lane, and S300K at 12″ where one line must swallow an apron's whole peak without an intermediate outlet. Ductile iron grates, locking options across the range, and a rail-and-frame system that survives track shoes and pivot steers. ACO is quote-only and never goes through the cart on purpose: channel, grate, lock, frame, end caps, outlets and in-line basins get matched as one system against your class and invert. Request a quote with run length, class and the heaviest vehicle that stops on the line.
Best for the gate, the plaza and the motor pool aisle — ACO KlassikDrain
What we reach for when pavement is serious but not tactical, and when appearance or grate variety matters. K100 at 4″ handles ACP plazas, headquarters forecourts and memorial walks with a grate catalog broad enough to satisfy an architect; KS stainless-edge variants earn their keep where a rail takes constant abuse from wheels tracking the same line. K200 at 8″ and K300 at 12″ carry motor pool aisles, dock aprons and bus lanes. Where a threshold or tight retrofit leaves almost no depth, MiniKlassik K50 is the small-format answer. Quote-only through RFQ, same as PowerDrain.
Best line a public works shop can order this afternoon — NDS Dura-Slope
Housing, admin, MWR & light-fleet aprons · in the cart today
Most of the linear footage on a base is not tactical, and Dura-Slope is what we spec for it. Built-in slope keeps water moving on dead-flat pavement without shimming every section, and the grate range spans plastic through metal, including turf-tone colors that disappear into a housing streetscape. Being orderable directly matters when a shop needs stock on the shelf instead of a two-week quote cycle for a repair. Know the ceiling honestly: this is the answer for housing streets, admin drives, MWR pavement and light-fleet aprons. When a HEMTT parks on it, step up to ACO. Detail in the Dura-Slope FAQs.
Best for family housing and the repair stockroom — NDS Pro Series
3″ · 5″ · 8″ · 12″ · in the cart today
The residential and light-commercial backbone, and the one line where sizing is a genuine four-way choice rather than a default. 3″ for a single housing driveway or patio run; 5″ as the workhorse across a full-width driveway or garage threshold; 8″ or 12″ when tributary area or a long single-outlet run demands the conveyance. Deep dives: 5″ Pro Series resources and 8″ Pro Series resources.
Best accessible-route and gate-walkway pick — BG Filcoten TEC
V100 · V200 · V300 · fiber-reinforced HPC · in the cart today
Fiber-reinforced high-performance concrete gives a channel that behaves like heavy commercial hardware while staying orderable from the catalog — useful when a project cannot absorb an RFQ cycle but the pavement deserves better than plastic. We reach for TEC V100 at 4″ on accessible routes and gate walkways where a heel-safe grate pattern and a clean edge matter, and step to V200 at 8″ or V300 at 12″ where pavement gets heavy and runs get long. See the Filcoten grate range and Filcoten resources.
Best low-point collection and cleanout — catch basins
Every zone · the cheapest insurance on post · in the cart today
Wherever a channel run ends, two grades meet, a plow pile melts, or a vac truck needs somewhere to put a hose, you want a basin rather than a buried tee. Size it for storage and service, not just flow: 12″ at housing and walkway low points, 18″ and 24″ anywhere sediment is part of the diet — on a motor pool or wash rack, everywhere. Kits and risers get you to grade, outlets and adapters tie into existing pipe, and the grate matches the pavement around it: ductile iron or cast iron where wheels cross, atrium grates in landscape where leaves would blind the inlet.
Sidewalks, thresholds & shop entries · shallow trench · in the cart today
Most base drainage work is not new construction — it is a fix inside a slab poured decades ago, above a utility nobody wants to find. That is where the shallow lines earn their place: enough capacity for a walkway, door threshold, courtyard or shop entry, in a trench you can realistically cut. Match the grate to the traffic honestly. A shallow channel with a pedestrian grate does not become a vehicle drain because a vehicle drove over it once.
Buying it on a federal job: submittals, substitutions & origin
We are a distributor, not the designer of record, and on installation work that distinction is the most useful thing we can tell you.
Or-equal requests. If the drawings name one manufacturer and you want to price another, tell us which criteria matter — class, clear opening, invert depth, outlet configuration, grate fixing — and we will tell you where the candidate matches and, more usefully, where it does not. Approval is the designer's call.
Castings outside our stocked ranges. Where the design calls out heavy frames, covers or trench castings we do not stock, we quote ABT, EJ and U.S. Foundry on request, and the Josam Pro-Plus channel line the same way. Send the spec section and detail sheet rather than a part number — on federal work an approximate match comes back as a rejected submittal three weeks later.
Delivery to a controlled site. Gate hours, escort requirements, receiving windows, forklift availability and whether a truck can reach the pour location belong in the quote conversation, not in a surprise call from a driver at the visitor center.
Turnaround. Send drawings, spec section, run lengths, load class and invert depths and we come back with a takeoff and quote within one business day.
Worth planning too: a public works shop is better served holding stocked spares than quoting every repair. Grates walk off, frames get plowed, basin lids crack. Keeping common grates, fittings and valve boxes on the shelf turns a two-week procurement into an afternoon work order.
Frequently asked questions
What load class does tactical vehicle pavement need?
Class D 400 kN, a test load near 90,000 pounds, is the floor for any pavement a military truck uses. Step to Class E 600 kN, about 135,000 pounds, where tracked vehicles, HET and PLS rigs or loaded material handling equipment stop and steer on the grate line, and Class F 900 kN, about 202,000 pounds, where the designer of record marks the heaviest pavement on post. H-20 read as a 16,000-pound wheel load and HS-25 as 20,000 pounds is a trade heuristic, not an equivalence to EN 1433.
Can I order ACO PowerDrain online for a base project?
No, and that is deliberate. Every ACO line we carry, PowerDrain and KlassikDrain alike, is quote-only and never goes through the cart, because channel body, grate, lock, frame, end caps, outlets and in-line basins have to be matched as one system before anything ships to a job with a submittal register attached. Send run length, load class, invert depth and the heaviest vehicle that stops on the grate line, and we quote within one business day.
How do I size the trench at a vehicle wash rack?
Size it for the wash water, not the weather. Sum every nozzle that can physically run at once, since hand wands run roughly 4 to 6 gpm each and tactical rinse arches run far higher, then add rainfall at roughly 623 gallons per 1,000 square feet per inch if the pad is open to the sky. Then check the outlet: flowing full at 1 percent slope, 6-inch pipe carries about 250 gpm, 8-inch about 540 gpm and 10-inch about 985 gpm.
Do you supply oil-water separators or wash-water reclaim equipment?
No. Separators, grit and sand interceptors, reclaim skids, lift stations, pumps and any form of treatment sit downstream of us and are supplied by others. We sell the surface collection layer that feeds them: the channel across the pad, the grate that takes the axle, the sediment bucket, the basin at the low point. At fuel points and hazardous-material pads the containment itself is engineered work by others.
Do you sell french drains for training fields and parade grounds?
No, and nothing in our catalog is a french drain. A french drain is a subsurface system: perforated pipe, commonly 4 to 6 inches, bedded in washed stone and wrapped in geotextile, cut in to move groundwater rather than catch water off a surface. Installations use them under PT fields and parade grounds, along soggy training-area shoulders and as edge drain beneath pavement base. That is excavation work by a site contractor; we supply the surface layer above it.
Can grates be locked down so they cannot be lifted or become FOD?
Yes, and near an airfield or inside a controlled area you should insist on it. A loose grate near a movement area is foreign object debris, and a grate that lifts by hand at an access control point is a security question rather than a drainage one. ACO offers locking and boltdown grates across the range, and metal grates on our NDS and Filcoten systems fix to the frame. Set frames 1/8 to 1/4 inch below finished pavement.
Will you provide submittals and country-of-origin information for a federal contract?
We furnish manufacturer cut sheets, load-class documentation, dimensional drawings and published literature so you can assemble the submittal package your spec section requires, and we state the country of origin the manufacturer publishes for anything we quote. We do not certify compliance on your behalf: domestic-preference determinations and or-equal approvals belong to the designer of record and the contracting officer.
Speccing drainage for an installation project?
Send the drawings and spec section with run lengths, load class, invert depths, and the heaviest vehicle that crosses the grate line — we'll take off the full system, flag anything that belongs to another trade, and quote it within one business day.
