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Spiral duct looks simple from the outside. A coil of metal, a lockseam, some fittings. But fabricating it to SMACNA-compliant pressure classes, diameters ranging from 4 inches to 60-plus inches, and gauges matched to negative pressure ratings for New Jersey commercial code? That’s where the gap between a real manufacturer and a catalog distributor becomes painfully obvious on inspection day.
At HVAC Metals, LLC, we fabricate round spiral duct, flat oval, and custom fittings out of our shop at 181-183 Garfield Ave, Kearny, NJ 07032. We’ve been doing this since 2015, and the one thing that hasn’t changed is that contractors across Jersey City, Hoboken, Secaucus, Bayonne, North Bergen, and Union City still run into the same core problem: a supplier who can’t commit to a real gauge spec, a real pressure class, or a real delivery time.
We can. So let me walk you through how we actually operate.
I’ve seen foremen get to rough-in inspection in Jersey City high-rises and get flagged because the spiral duct on-site was fabricated to CL6 when the mechanical schedule called for CL3. That’s not a minor paperwork issue. That’s a stop-work order and a re-fabrication bill nobody budgeted for.
SMACNA leakage class defines how much air a duct system is permitted to leak per unit of surface area at a given pressure. For most commercial and multifamily applications in Hudson County, CL3 is the standard target, though CL1 shows up on sensitive institutional jobs near places like Christ Hospital in Jersey City or academic buildings in Hoboken. CL4 might be acceptable for certain low-pressure supply branches, but you need to confirm that with your mechanical engineer before we cut anything.
When a project manager sends me a takeoff for a warehouse retrofit in the Secaucus Meadowlands corridor near Route 3, the first question I ask is: what’s the design static pressure, and what’s the longest unsupported span? Because those two factors drive the gauge call more than anything else.
The spiral lockseam itself adds rigidity compared to longitudinal seam duct, which is part of why spiral performs well in long straight runs with extended hanger spacing. Our shop rolls these on automated lines and plasma-cuts fittings on CNC tables, so the dimensional tolerances are tight enough that your field crew isn’t shimming or grinding on a roof deck in Bayonne in February.
If your mechanical schedule specifies negative pressure collapse resistance to -4 in. w.g., tell us that upfront. We’ll brace and gauge accordingly. This isn’t something to sort out after fabrication.
Hudson County’s built environment creates some material selection challenges that out-of-area suppliers genuinely don’t think about. The waterfront along Jersey City and Bayonne sits right on Newark Bay and the Hudson River. Salt-laden air penetrates mechanical rooms, rooftop equipment, and exposed duct runs faster than most project specs anticipate.
Standard G90 galvanized steel holds up fine in interior shaft applications and conditioned spaces. But on exposed or semi-exposed runs near Port Jersey or the waterfront redevelopment zones in Jersey City ZIP codes 07302 and 07305? G90 starts showing corrosion at cut edges and transverse joints within a few years if the system isn’t sealed aggressively to ASHRAE 90.1 requirements.
For lab exhausts, food service kitchen makeup air, and pharmaceutical clean rooms, we fabricate in 304 or 316 stainless. It’s not a cheap upgrade, but it’s the right call when the alternative is a failed inspection or a duct system that degrades inside a controlled environment. (I’ve seen a food service project in Union City where the contractor tried to save money on G90 for a grease exhaust application. That duct was pulling apart at the seams within 18 months. Not a fun conversation to have.)
PCD (polyvinyl-coated ductwork) and galvanneal are options we carry for highly corrosive exhaust environments where stainless is over-specified but G90 is under-specified. If you’re quoting a lab or an industrial process exhaust in Hudson County and you’re not sure which material to spec, call me before you submit the bid. We can sort it out in a 10-minute conversation.
For rooftop structural applications where RTU support rails and equipment platforms matter, aluminum is often the right call: lighter load on pre-war roof decks, no corrosion risk in exposed conditions, and easy to cut and fit in the field.
See how we approach commercial ductwork material selection for top contractors when the application is more complex than a standard supply run.
Logistics is where most fabricators fall apart. Not in the shop. On the road.
I run an in-house fleet of box trucks out of Kearny. When we commit to a 6:00 AM delivery to a jobsite on Marin Boulevard in Jersey City or Observer Highway in Hoboken, that truck is on your deck at 6:00 AM. Your crew clocks in at 7:00, duct is staged, and they’re installing from the first hour. Compare that to a late afternoon freight drop from a regional supplier stuck on the Pulaski Skyway approach while six mechanics burn through their shift standing around. At Hudson County labor rates, that’s not an inconvenience. It’s a line-item loss on your P&L.
Can spiral duct be delivered directly to high-rise floors in Jersey City or does staging always happen at street level? Practically speaking, almost all urban deliveries in the Journal Square and Exchange Place corridors require street-level staging, coordinated with the super or GC site manager. We handle that coordination on our end when we schedule. We know the loading dock constraints on Kennedy Boulevard and the narrow access points near Grove Street. This isn’t something we figure out the morning of delivery.
Secaucus warehouse projects off Route 3 near Croxton Yard are a different animal. Those sites typically have dock access and more staging room, but they come with their own timing constraints tied to receiving windows and multi-trade coordination. We schedule flatbed drops for large-diameter duct sections based on your mechanical foreman’s sequence, not our convenience.
Deliveries into Bayonne along Route 440 near the Port Jersey terminal area require early staging before port traffic builds up. We’ve run enough loads through that corridor to know when to leave Kearny and which approach avoids the worst of it.
Legacy supply houses are still running paper-based take-off workflows. You submit a blueprint, they scale it manually, and three days later you get a lump-sum number with no line-item breakdown by diameter, gauge, or material. That’s useless when you’re putting together a competitive bid for a design-build GC in Weehawken who needs a hard number by Thursday morning.
We ingest digital take-offs, architectural files, and mechanical plan sets through our estimating software and return itemized quotes within 4 to 24 hours. Line items show diameter, gauge, material specification (G90, stainless, aluminum), leakage class, and fabrication notes aligned with the NJ Uniform Construction Code. Your estimator gets something they can actually work with, not a number they have to reverse-engineer.
What lead times should Hudson County mechanical contractors expect for custom spiral duct fabrication? Standard G90 galvanized spiral sections in common diameters typically run 3 to 5 business days from confirmed order. Specialty materials, large-diameter sections above 36 inches, double-wall acoustic assemblies, or stainless steel runs carry longer lead times that we’ll confirm at quote stage. Urgent bid-cycle requests get flagged and we’ll tell you honestly if we can hit your date. If we can’t, I’d rather tell you upfront than have you find out the day before rough-in.
Check out our approach to SMACNA Class A compliance and how seam welding precision affects your air leakage test results if you’re working on a spec-heavy commercial project where documentation matters at inspection.
Hoboken and Jersey City waterfront towers are dense. Mechanical rooms sit directly adjacent to residential units or office tenant floors. NJ Uniform Construction Code and local mechanical ordinances in these municipalities have gotten stricter about transmitted noise from duct systems, particularly in mixed-use buildings where HVAC noise from a commercial kitchen exhaust can bleed into a residential corridor two floors up.
Double-wall acoustic spiral duct solves this. The outer shell is standard galvanized spiral, the inner liner is perforated metal, and the cavity between them is filled with glass fiber or mineral wool insulation. The perforated liner absorbs airborne sound energy before it transmits through the duct wall. Thickness runs from 1 inch to 2 inches of insulation depending on the acoustic rating required by the mechanical engineer’s spec.
We fabricate double-wall sections in-house. Fittings (elbows, reducers, taps) are also available in double-wall configuration, which matters because acoustic performance falls apart at the fitting if you’re transitioning from lined straight sections to bare sheet metal elbows.
How does double-wall spiral duct handle tight mechanical shafts in Hoboken brownstones or pre-war buildings in Union City? Flat oval configurations are the answer for most of those retrofit situations. A flat oval duct maintains the aerodynamic efficiency of round spiral but fits into shafts with limited vertical clearance. We fabricate flat oval in galvanized and aluminum, with fittings that coordinate with existing rectangular duct systems where you’re doing a partial retrofit rather than a full rip-and-replace.
Retrofit jobs in older Hoboken and West New York rowhouses are genuinely some of the more interesting fabrication puzzles we get. The shaft dimensions are whatever they are, the ceiling height is fixed, and the mechanical engineer wants round duct. So we’re producing custom flat oval transitions, offsets, and saddle connections that fit what’s actually there, not what the textbook says should be there.
Fragmented procurement is expensive. When a project manager sources spiral duct from one fabricator, transverse joint sealant from a plumbing supply house, and clevis hangers from a separate distributor, the purchase orders multiply, the delivery timelines never quite align, and somebody’s foreman is on-site with duct but no hardware to hang it.
We stock and bundle the full installation package with every fabrication order: threaded rod, trapeze hangers, clevis hangers, strap supports, duct sealant, drive cleats, and slip connectors. Support spacing gets confirmed against SMACNA hanger requirements based on duct diameter and weight. Your crew gets everything they need to install from the staging area without a second trip to a supply house.
Sealant selection matters more than most people acknowledge. ASHRAE 90.1 mandates sealing at all transverse joints, longitudinal seams, and duct penetrations for conditioned air systems. In New Jersey’s energy code environment, that’s not optional. We supply UL 181-listed sealant appropriate for the duct class and material so there’s no question at inspection about product compatibility.
I want to be straightforward about this: we’re not a wholesaler in the traditional sense. Our one-stop model grew out of contractor feedback over the years telling us that coordinating three separate vendors for one duct run was burning time nobody had. So we made it simpler. That’s genuinely why we built it that way, not as a marketing angle.
Our full custom ductwork fabrication and supply capabilities are outlined on our services page if you want the full scope before you reach out.
Our core customers are mechanical contractor project managers and estimators running HVAC scopes on multifamily towers, commercial office fit-outs, institutional facilities, and warehouse industrial work across Hudson County. Jersey City and Hoboken waterfront projects are a regular part of our workload. So are the big-box and cold storage facilities in the Meadowlands industrial corridor off Route 3 near Secaucus.
Facility managers and directors of operations at commercial campuses, data centers, and healthcare facilities in Hudson County also reach out regularly for retrofit ductwork, tenant improvement ventilation, and energy upgrade projects where replacing inefficient rectangular duct runs with properly sized round spiral makes an operational difference.
We also work directly with HVAC foremen who need to confirm dimensions, request shop drawings, or adjust an order mid-project when field conditions don’t match what was drawn. That kind of direct, technical communication with the person actually running the job is something I take seriously. The foreman who calls me at 7:30 AM because a shaft dimension is off gets the same attention as the project manager submitting a full mechanical takeoff.
If you’re early in a project and need takeoff support, shop drawings, or a technical review of your duct pressure classes and material specs before you commit to a bid, reach out through our contact page and let’s get into the details.
Stay connected with us on LinkedIn and Facebook for project updates, fabrication insights, and the occasional behind-the-scenes look at what comes off our shop floor.
Written by: Arthur Dabrowski
HVAC Metals, LLC
(201) 991-2206