The Heating, Ventilation, and Air Conditioning industry is responsible for providing the comfortable indoor environments we find in residential and commercial buildings. This industry sector is made up of manufacturers, suppliers, installation contractors, and service contractors, all of whom utilize a wide array of mechanical hardware and fasteners in their day-to-day operations. As the first article in our new Applications series, we’ll discuss below the most common types of hardware utilized in HVAC projects.
Understanding hardware options in the HVAC world begins with a quick review of the regulatory landscape involved in this industry. To introduce some terminology, we’ll use the words Systems, Equipment, and Components. Within a building, an entire HVAC System is made up of various pieces of Equipment (such as air conditioners and blower fans), and Equipment is made up of, and installed using, many more different Components (such as ducting, supports, thermostats, and sensors).
HVAC systems are typically governed by construction codes (EG. UBC, NEC, NFPA) at the national and local levels. Equipment is covered by HVAC industry standards associations (EG. ASHRAE, NIST, AHRI), and components are covered by specific functional standards associations (EG. ASTM, ANSI, ASME).
When selecting hardware for the HVAC industry, buyers are encouraged to confirm which codes they must comply with, so that selections are sure to be compliant and not at risk of being challenged during assembly or construction inspections. When buying hardware for system and system installation use, check specifications against the mechanical engineer’s or builder’s project requirements. When buying hardware for equipment assembly use, check specifications against the equipment manufacturer’s original fabrication or service requirements.
Once the applicable standards and regulations are identified, the next thing to understand is the combined performance and functional requirements specific to the application at hand. As we’ll see in the next section, hardware selections are most commonly made by pairing a style of hardware with a material choice that together fits the technical demands of the application’s environment and operating conditions.
Lastly, since the HVAC industry has so many regulators, manufacturers and contractors involved, simplifying and standardizing hardware options has been a major industry-wide objective of the last few decades. The industry has worked towards a uniform series of hardware options that can be widely found at hardware stores, commercial resellers, and industrial distributors across the country. For this reason, buyers of HVAC industry hardware should always solve for their application’s specific technical demands first, but otherwise look to utilize common, generally-available hardware as much as possible.
Do you have an HVAC application but are unsure of which fastener meets your project’s requirements? E&T Fasteners offers expert support and product selection between the above options and more! Contact us to discuss your application, or to see our entire fastener catalog, visit our product selection here.
HVAC Hardware Application Types
In the below examples, we’ll bundle hardware options together by their most common use-cases seen during field installation. Equipment assembly is typically highly specialized, so we’ll leave further discussion on these engineered fastener options to the last section of the article discussing materials and features.
| Application Category | Common Hardware Components |
Fig. 1 – HVAC Suspended Strut Hardware  | Indoor installation of HVAC equipment, piping and ducting typically utilizes suspended strut trapeze hangers, anchored into each room’s ceiling. Strut trapezes or racks are easier ways to support multiple ducting runs than hanging each independently. Consideration must be given to the weight capacity of the ceiling structure. Wall hangers are just as common for vertical drops, anchoring strut directly to walls. Common hardware includes: Threaded rod, couplings, stiffeners, sleevesUnistrut and formed-channel hangers, channel nuts, channel washersStrut clamps, straps, and brackets Seismic supportsConcrete ceiling and wall anchors |
Fig. 2 – HVAC Rooftop Support Hardware  | Rooftop piping, ducting and component supports look very similar to the above suspended strut racks, but extend above the roof structure with rigid strut framing instead of threaded rod drops. Anchor points are notably different, requiring large anchor pads that adhere to the roof material without penetrating it, in order to spread out the weight of the supported gear and not create leak points through the roof surface. Large equipment will have structural supports through the roof material to the building’s roof framing or down to the foundation below. Unistrut and formed-channel hangers, channel nuts, channel washersRoof footpads or “sleepers”, adhered with mastic or other adhesivesStrut clamps, straps, and brackets Seismic supports |
Fig. 3 – HVAC Cable Supports  | For single ducting runs of smaller diameters and lower weights, cable supports are very common especially in light commercial and residential construction. Cable hardware is inexpensive, easy to install, and long-lasting. Cabling is also very often used in HVAC projects as secondary and seismic restraints, such as for tall vertical exhaust stacks where heavy structural supports would be overkill. Cable, wire, and cable setsClips, sleeves, crimp ends, and cable clampsAnchoring ends such as L-brackets, flat brackets, eyelets, and thimblesTensioning hardware such as turnbuckles, cams, and winch ends Attachment hardware such as links, carabiners, grips, and snapsAbrasion protection sleeves and guides |
Fig. 4 – Ducting Fasteners  | Constructing and installing ducting is inherently a type of sheet metal fabrication work. For this reason, most hardware used for ducting consists of simple sheet metal fasteners with a few added features targeting specific applications. Self-tapping, self-drilling screwsFor no-leak fastening into air ducting, special sheet metal screws with gasketed heads are used “Tek” and “Zip” screwsTamper-proof screws For flange connections, standard hex-cap and round head bolts, nuts, and washers are usedFlange gasket tape |
Fig. 5 – Assorted Hardware  | As with most construction trades, HVAC work taps into the wider general hardware pool in order to round out any given project. Since every project is different, installers and equipment builders alike will at some point pull all from sorts of commodity components to meet their needs. Standard hex, round, pan, and flange head bolts, washers, and nuts quick-connect hardware such as wing nuts, pins, clips, and clamps Structural hardware such as carriage bolts, rivets, and anchors |
Materials and Features
Most HVAC applications have different attributes that influence our hardware selections, depending on which part of the system and building space we’re working in. Let’s break down these attributes into fastener grades:
- Indoor components are often dry, clean, and at normal temperatures, calling for general grade hardware
- Outdoor components are often fully exposed to the elements, including all-day sun exposure being on top of building roofs, calling for weather-rated hardware
- Components installed within HVAC equipment are often exposed to harsher conditions, with high or low temperature, humidity, vibration, and general stress, calling for high-grade hardware
- Certain critical equipment areas will require even higher-performance components, such as within refrigeration compressors, heater burner trains, and high-speed blower fans, calling for specialty engineering hardware
Using the above grades, buyers should consider the following material and feature specifications as a starting point, and then should discuss their application with a trained distributor to finalize their selection.
- General Grade Hardware – aluminum, brass, zinc-plated steel or bronze material with no applied finish; with standard threads
- Weather-Rated Hardware – steel with zinc, nickel, or galvanized plating; stainless steel type 18-8 or 304 with no applied finish; with standard or fine threads, and thread-lock compound
- High-Grade Hardware – high-strength steel with zinc or nickel plating; or stainless-steel type 316; heat treated; with fine threads, thread-lock compound, and high-temp coating if needed; structural grade / class if needed (imperial Grade 2 and 5 / metric Class 8 and 10 common)
- Specialty Engineering Hardware – stainless steel type 316, Hastelloy, forged steel, or other exotic materials; plated, coated, and / or annealed as needed; heat-treated; structural grade / class if needed (imperial Grade 8 / metric Class 12 common)
- Around electronics and electrical circuits, other special hardware requirements may call for non-conductive / non-metallic fasteners using bronze or plastic materials
E&T Fasteners is here to help you navigate fastener and accessory options. Price quotes, availability, lead times, delivery confirmations, unique application suggestions – whatever your need, we’re here to take your call or email. For support and advice from our fully trained staff, speak with an E&T sales representative today.
About E&T Fasteners
With sales and support teams spanning the Continental US, E&T Fasteners is here to serve your hardware, fastening, and component needs both domestically and internationally. We are a stocking distributor of metallic, plastic, and exotic alloy fasteners, backed by our technical staff directly experienced in your unique applications. We can assist your specifying and selection efforts, providing engineered solutions, record-fast lead times, and stellar customer service from quote through delivery. Please let us know how we can help!
