What Does a Dry Chemical Skid Cost? A Breakdown by Size, Agent and Options

No manufacturer publishes a list price for a dry chemical skid, because almost every unit is configured, so a buyer comparing quotes is really comparing configurations. Cost is set by seven things, in roughly this order of weight: agent capacity, materials of construction, the number and length of hose reels, the agent itself, the nitrogen supply, the options list, and whatever it takes to get the unit installed and commissioned. A 350 lb carbon steel skid with one reel and sodium bicarbonate sits at the bottom of the range. A 2,000 lb unit in 316 stainless with dual reels, Purple K and an offshore coating system sits several multiples above it, and the gap between those two is wider than the gap between most manufacturers' prices for the same configuration.

Capacity: the tank sets the baseline

Agent capacity decides the size of the pressure vessel, and the vessel is the single largest component. A tank fabricated and tested to ASME Section VIII scales with diameter, wall thickness and the number of openings, and a 2,000 lb vessel carries far more steel, welding and inspection time than a 350 lb one. The frame, lifting points and cylinder cage grow with it, and so does freight. Capacity does not scale the price linearly, though. Doubling the agent from 1,000 to 2,000 lb does not double the cost, because the hose reel, regulator, valves and nozzle are close to the same on both, so the larger unit is usually the cheaper one per pound of agent. That argues for buying the capacity the hazard needs rather than the smallest unit that fits the budget, with the quantity following from the hazard area and the discharge time the design calls for. Salus Global builds 350, 1,000 and 2,000 lb as standard, and a hazard that needs more agent than that, or needs the discharge to start without an operator, has outgrown the skid format and prices as an engineered fixed system with its own design phase.

Materials and coatings: the biggest multiplier after size

A skid on a loading rack in Oklahoma is carbon steel with an industrial paint system. One on a jetty, a Gulf of Mexico platform or a coastal LNG export terminal is a different article. Salt air attacks carbon steel at every weld and edge, and the choice is between a marine coating system over carbon steel, which adds surface preparation, multiple coats and inspection, or 316 stainless for the tank, frame, piping and reel, which adds material cost and more demanding fabrication. Stainless is the larger step: on a 2,000 lb unit the gap between a painted build and a full stainless one is commonly the largest single line item after the vessel. Mixed builds sit between, such as a stainless tank and piping on a coated carbon steel frame. Sour service adds material certification and, on some sites, NACE compliant components in the gas path. The honest way to price this is to match the material to the environment and the expected service life, not to the most corrosion resistant option available, because a painted unit at a dry inland site will outlast the plant it protects.

Hose, reels, agent and nitrogen

Hose and reels are where two identical-looking skids diverge. A single reel with 50 ft of hose is the minimum. A reel with 100 ft, a second reel on the opposite side so two operators can attack from both directions, a swivel reel for a jetty, or a stainless reel offshore each add cost, and nozzle selection follows hose size. On a loading rack with bays on both sides the second reel is the cheapest way to cover the geometry; on a single pump house it is money not needed.

The agent is a smaller share than most buyers expect. Sodium bicarbonate is the cheapest per pound, monoammonium phosphate is close to it, and potassium bicarbonate (Purple K) costs more, with the specialist agents such as Monnex above that. Purple K is roughly twice as effective per pound on Class B fires as sodium bicarbonate, so on an effectiveness basis it is rarely the expensive choice, and it is the usual petrochemical and LNG fill. The agent bill also recurs: a discharge or a failed agent check at semi-annual maintenance means a refill, so the ongoing cost of the unit is tied to agent price in a way the purchase price is not.

Nitrogen is priced by cylinder count and fittings. A skid carries enough cylinders at 150 to 200 bar to expel the full charge at the design flow rate, and the count rises with capacity. Cylinders, valves, manifold and regulator are commodity items and a modest share of the total, though a spare cylinder set for fast recommissioning after a discharge is an option buyers often overlook.

Options and the installation line

The option list is the part of the quote a buyer should read closely. Common items include a weather canopy, a forklift or crane lift frame, trailer mounting for a unit that moves between hazards, remote discharge indication to the plant panel, heat tracing for cold climates, low pressure alarms on the cylinders, explosion-proof fittings in a classified area, and documentation or third party inspection packages. Listing should not appear as a priced extra, because a Salus skid is UL 1254 listed as built. Certification for marine and offshore use, with USCG approval in progress for the Salus range, is a separate discussion that affects materials and documentation.

Installation is the line that depends least on the manufacturer. A skid is delivered on a truck, set on a pad or a steel deck, and needs no piping, water or power. The site cost is the foundation or deck reinforcement, the crane lift, anchoring, any enclosure, and commissioning: a functional check of the cylinders and regulator, a hose lay and a tag. A unit delivered filled from the factory commissions quickly; one shipped with agent and cylinders separately needs a site fill first. On an offshore platform the lift and the deck modification dominate everything else, and on a remote site freight can be a noticeable fraction of the unit price.

Cost driver	Low end	High end	Relative effect
Capacity	350 lb	2,000 lb	Largest, but less than linear
Materials	Painted carbon steel	316 stainless, offshore coating	Largest multiplier after size
Hose and reels	One reel, 50 ft	Dual stainless reels, 100 ft each	Moderate, roughly doubles reel content
Agent	Sodium bicarbonate	Purple K, Monnex	Small share of purchase, recurring on refill
Nitrogen	Standard cylinder set	Extra cylinders, spare set	Modest
Options	None	Canopy, trailer, alarms, Ex fittings	Variable, read the list
Installation	Pad, forklift, site fill	Offshore lift, deck work	Site dependent, not manufacturer dependent

Lead time is a cost too

A price is only comparable at the same delivery date. It is common to be quoted, by buyers' own accounts, twenty weeks or more from the established brands for a configured skid, and on a construction project where fire protection is on the critical path for commissioning, a late skid can hold up a turnover or push a contractor into a temporary hire. Where a unit is being replaced after a discharge or a failed inspection, a long lead time means either a gap in protection or the cost of a rental unit in the meantime. A buyer comparing two quotes with a twelve week difference in delivery should put a number on that gap. Manufacturers that assemble, fill and inspect domestically, as Salus does at its Texas facility, can hold standard sizes closer to stock and build configured units in a shorter window.

What a supplier needs to return a firm number

A budget price can be given from capacity and materials alone. A firm quote with drawings needs more, and sending it with the inquiry saves a round of questions:

• The hazard: what is protected, its area and the fire scenario, so the supplier can confirm capacity and hose reach.
• The agent, or the hazard type if the buyer wants a recommendation.
• The environment: inland, coastal, offshore, sour, cold, classified area.
• The reel configuration, or the site geometry so the supplier can propose one.
• The listing and approval requirements, UL 1254 as a minimum and FM Approval if the insurer asks.
• Delivery point, required-on-site date, and whether the unit arrives filled or is filled on site.

With that, a manufacturer can return a price, a general arrangement drawing with weights and footprint, and a delivery date that procurement can hold them to.

Frequently asked questions

Is a dry chemical skid cheaper than a fixed foam or water spray system?

For an open-air Class B hazard, usually yes by a wide margin, because the skid has no pumps, fire main, proportioner, piping or nozzle network, and no water supply. The comparison changes where the hazard is a large pool fire that dry chemical cannot hold, or an unmanned hazard that needs automatic fixed protection. The fair comparison is cost per protected hazard over the life of the system, including inspection and refills.

How much does it cost to refill a dry chemical skid?

The refill is the agent by weight, the nitrogen cylinder recharge or exchange, and the technician's time for the fill, cylinder fitting, functional check and tag. Purple K costs more per pound than sodium bicarbonate, and a 2,000 lb refill is a meaningful agent bill. Skids with separate nitrogen cylinders can be refilled on site, which avoids freight and the downtime of sending the unit out. The refill sits inside a larger ownership cost that belongs in the same budget line as the purchase: a monthly owner inspection, semi-annual maintenance by a technician for as long as the unit stands there, and a hydrostatic test of the vessel and cylinders at twelve years, which empties and refills the skid whether or not the agent had failed.

Why do quotes for the same capacity vary so much?

Because the capacity is the only thing that was the same. Materials, reel count, hose length, agent, options and the documentation package all move the number, and one quote may include freight, filling and commissioning while another does not. Ask each supplier for a line-item breakdown against the same specification before comparing totals.

Salus Global dry chemical skids are UL listed and assembled, filled and inspected at our facility in Texas. Call +1 360 901 9828 or email info@salusglobal.co.