How to Evaluate Wet Scrubber Manufacturers Before You Buy

You’re staring at three quotes on the desk. They have the same CFM, and the same FRP housing, and the prices are close enough that you might as well flip a coin.

You won't, because your name goes on the spec. And the details that decide whether that scrubber runs clean for years or turns into a punch list usually aren't on the quote at all. That includes how the body was laminated, where the bonds are, who plumbs it, and whether the fan was sized to its pressure drop.

The fix is to ask every bidder the same questions, in the order you'd buy.

Key Takeaways

• A quote built without your process data rests on assumptions. Ask the manufacturer which values they assumed for ACFM, contaminant loading, temperature, and removal efficiency.
• Drawings before the PO keep a real unit in your plant model. Ask for the footprint, height, weight, and connection points in your CAD format before there's an order.
• "FRP" on a quote doesn't always describe the laminate. Get the veil, mat plies, barrier thickness, and resin in writing, and ask how internal plates are supported.
• A reliable manufacturer will run a plumbing and water test, checking the valves, pumps, and sensors before they ship. A scrubber that ships as a bare shell leaves the plumbing to the installing contractor.
• Size the fan to the scrubber's actual pressure drop. A manufacturer that builds the fan and duct should size them to the unit they design for you, not a generic estimate.

What a Manufacturer Asks You Reveals How It Will Design the Scrubber

The first quality check happens before any price shows up. Look at what each manufacturer asked you for, because a quote is only as good as the process data behind it. At a minimum, that means inlet ACFM, contaminant loading, temperature, and required removal efficiency, plus a few configuration choices.

The wet scrubber install guide lists all eight design inputs and how they shape the unit.

If a quote comes back without some of those, the manufacturer assumed them for you. That's not automatically or necessarily wrong, but be sure you ask which values it used. Airflow isn't the only thing that sets size; a tighter removal target can call for a bigger unit, and a very fine outlet particle limit can call for a special mist eliminator that adds height.

What You Should Get Before the Purchase Order

Ask whether the manufacturer will give you a drawing of your scrubber before there's an order. You need it to lay out the plant, and you need it while the design is still moving.

We see this a lot. When an engineering team hasn't worked with scrubbers all that much, the scrubber goes into the 3D model as a plain rectangle, a placeholder until the real unit turns up. That works until the real unit is taller or the hookups land somewhere the layout didn't plan for.

So ask what the drawing will show. You need the footprint, the height and width, the weight, and where every hookup lands. You don't need the internals; that's the manufacturer's problem.

We'll design a scrubber to your general specs and send the drawing in AutoCAD, Revit, or your model's 3D format before a PO. Every scrubber we design is different, so it's one-on-one, not a library download. It's also the right time to ask which common options belong in the design, such as basket strainers, secondary containment, or additional sensors, so they show up on the drawing instead of in a change order.

The same test applies mid-design: which material holds up to which chemical at what temperature, what the fan curve looks like, what the system pressure drop adds up to. A manufacturer headed for your spec should answer those now, not after the order.

How the Scrubber Body Is Built

The quote will say "FRP." However, it won't say how much of that is corrosion barrier or how the internals are held in place. You want to get both in writing.

Ask for the laminate construction

In our FRP scrubbers, the inner surface is a resin-rich layer reinforced with surfacing veil, roughly 90% resin and 10% veil, backed by two plies of 1½ oz mat at about 75% resin. Together those make a 100-mil corrosion barrier. Structural layers of mat and woven roving give the walls and sump their strength, and a gelcoat exterior handles UV.

A complete written answer from any bidder should cover the same ground: the surfacing veil (ours is C-glass or a synthetic Nexus veil), the mat plies behind it and their resin content, the total corrosion barrier thickness, the structural layers, and the resin by name. If a bidder writes "vinyl ester FRP" and stops there, ask for the rest.

When two quotes both say FRP and only one can give you that breakdown, you've learned something about both.

It's also fair to ask how the body is built and checked. Ours goes from mold to corrosion liner, structural layers, and exterior finish, then assembly, plumbing and wiring, and a function test with final QC before it ships.

Ask how internal plates are supported

To hold an internal shelf, a fabricator can bond a plate to the scrubber wall. That bond means roughing up the edge hard so the fiberglass has something to grip, and the failure points sit right at those bond edges, where there are fewer layers. On our rectangular bodies, we bump the body out so the plate rests on it instead of being bonded in. Fewer internal bonds means fewer failure points.

Also, to be fair, round bodies are cheaper and faster to manufacture, and that can show up in the price. Either way, ask how the internals are supported.

Orientation is a trade-off, not a quality signal

Vertical units saturate the packing more easily and can run on a smaller pump and motor. Horizontal units sit lower and keep spray headers within reach, which suits rooftops and low ceilings. Neither is a quality signal on its own, so ask a bidder why it chose the orientation it did.

How Packed Bed Scrubbers Work covers the flow geometry.

Questions to Send Every Wet Scrubber Bidder

Five questions, in buying order. Ask each manufacturer the same ones, in writing.

What Arrives on Site

You should ask whether the scrubber ships plumbed and water-tested, or as a body with the plumbing left for the field. That answer decides how much work, and how much risk, lands on whoever installs it.

As standard practice, we fully plumb our industrial wet scrubbers in the shop and run water through them to check the valves, pumps, and sensors before they ship.

Then ask who shows up at startup. Our controls engineer programs our scrubber panels, and we can send the person who designed the panel to support startup. The install guide covers modular shipping, the contractor's pre-shipment visit, and startup in detail, and containment choices belong with the other options to settle before fabrication.

Whether the Scrubber Is Designed With the Rest of the System

A scrubber adds static pressure, and the fan has to be sized to that number, not a generic estimate. Ask whether the manufacturer builds the fan or hands its pressure drop to another vendor. We build PVC and fiberglass fans in-house, tested in accordance with AMCA Standard 210-67, and size them to the scrubber's pressure drop when we design the system (the logic behind industrial centrifugal blower selection).

The duct comes from the same company in SSTeelcoat coated stainless steel, FRP, or PVC. SSTeelcoat is where we steer corrosive exhaust runs when we can. FRP is a solid choice for scrubber yards and low-concentration streams, and PVC is the lower-cost option for lower-temperature air. When one manufacturer owns the scrubber, fan, dampers, and duct, there's one party to call when airflow comes up short.

Send Us the Same Questions

If you're writing a scrubber spec right now, send us the process data you have and the same questions you'd send any bidder, and ask for a drawing. Our engineering team averages about 25 years of tenure, and they'll lay out a unit you can drop into your model before anyone talks about a PO.

Viron has manufactured corrosive air handling systems for over 50 years across semiconductor fabs, municipal wastewater facilities, metal finishing operations, and industrial chemical applications. We'll tell you what we need to maintain your system properly.

Frequently Asked Questions About Wet Scrubber Manufacturers