Truss is the structural system that lets you hang lighting, audio, video, and scenic elements over an audience. It's also the line on an event bid that producers most often skim past because the math feels intimidating. The math is not intimidating; it's just specific. This guide is the working version of what you need to know to brief truss confidently, read a rigging plot, and ask the right questions when the engineering doc comes back.
Our crew flies truss at LA venues every week. Stadium concerts, hotel ballrooms, theatrical houses, warehouse-conversion brand activations, exterior brand builds. The truss math is the same in every venue; what changes is the venue's rigging capacity, the points the engineer signs off on, and the crew called to run the motors. Get the math right and the rest of the production sits on a stable platform. Get it wrong and nothing else matters.
For the broader context on how rigging fits into a typical event build, see our rigging service page. For the labor side — which union local does what, when the rigging crew has to call ETCP — see permitting and union labor in LA.
What truss actually is
Truss is a structural beam built from aluminum (sometimes steel) tubing welded into a triangulated lattice. The triangulation is what gives truss its strength relative to its weight — a 12-inch box truss section can span 30+ feet and carry a meaningful load without sagging, weighing only a few pounds per foot.
Three things define a piece of truss:
- Cross-section profile. Square, triangular, ladder-shaped, circular. Each has different load characteristics and is suited to different applications.
- Material and grade. Aluminum is the event-industry default. Steel (plated) is reserved for specific high-load applications.
- Connection system. How sections connect end-to-end. Conical-pin (Tomcat, Tyler) is the LA default. Fork-end (Layher) appears on some European-derived rigs. Spigot (Eurotruss F33) is common in Europe and increasingly in the US.
The producer doesn't need to specify the connection system — the rental house and the riggers handle it. The producer does need to understand the profile, because it determines what the truss is capable of and what it can hang above the audience.
Box truss — the workhorse
Box truss is the four-sided, square-profile beam that does the majority of the event industry's work. It typically comes in 12-inch and 20-inch sizes (referring to the cross-section dimension), with the 12-inch unit being the most common in LA event use.
Box truss can be hung from above (flown) or built up from the floor (ground-supported). It can be configured in straight runs, corners, and goals. It accepts standard event-industry attachment points (clamps, halfcouplers, eye bolts) and is rated to hang lighting fixtures, audio array boxes, and modest video screen weight without dedicated reinforcement.
The 12-inch box truss span chart producers should know roughly by heart:
| Truss Size | Typical Working Span | Approximate Load Capacity |
|---|---|---|
| 12" Box (Standard) | 20 – 40 ft | ~50 lbs per linear foot uniformly distributed, span-dependent. The workhorse. |
| 20" Box (Heavy) | 40 – 80 ft | ~100 lbs per linear foot uniformly distributed, span-dependent. Concert main grids, large goal posts. |
| 12" Triangle (Tri) | 15 – 30 ft | ~30 lbs per linear foot. Light fixtures, small banners, decorative use. |
| Ladder Truss | 10 – 20 ft | ~25 lbs per linear foot. Single-row lighting battens, drape support. |
| Circle / Curve | Custom radius | Variable. Used for scenic shapes, branded geometric installs. |
The capacity numbers above are general. The actual rated load for a specific truss section depends on the manufacturer, the section length, the support spacing, and whether the load is uniformly distributed or point-loaded. The rigger and the engineer compute the actual numbers for your specific show. The producer just needs to know that 12-inch box at a 30-foot span is the typical LA event grid — and that anything beyond about 40 feet starts wanting 20-inch truss.
Plated steel — when aluminum isn't enough
Plated steel truss is the heavy-duty alternative for high-load installations. It's used when the rigging plan calls for hanging weight beyond aluminum's safe working capacity, when the install will be in place for an extended period (theme park permanent installs, multi-month commercial fits), or when the engineer specifies steel for redundancy reasons.
Where producers see steel truss in 2026:
- Permanent venue installs. Theater chain ceilings, club permanent grids, broadcast studios. The truss doesn't come down for years.
- Heavy automation rigs. Motorized scenic elements with substantial mass — drapery winches, kinetic sculptures, large rotating set pieces.
- Large LED wall flown installs. The largest LED walls (60+ feet wide, fine-pitch) approach the upper limit of aluminum span capacity and may call for steel.
- Outdoor festival mainstage primary roof structures. Steel headers carrying the canopy load.
For a typical LA corporate event or wedding, plated steel is not on the bid. The producer working with steel is usually working on a permanent install, a major broadcast set, or a festival mainstage build. If the engineering doc proposes steel for an event without one of those drivers, ask why.
Motor pickup points — how the rig gets in the air
Truss doesn't fly itself. The truss is hung from motors (chain hoists, in industry terms) that are themselves hung from points the venue's engineer has approved. The motors haul the truss up to working height, then hold it there for the duration of the show.
The motor is rated by its load capacity, typically expressed in tons:
- 1/4-ton motor (500 lbs). Light grids, small banners.
- 1/2-ton motor (1,000 lbs). The LA event-industry workhorse. Most corporate events use 1/2-ton motors throughout.
- 1-ton motor (2,000 lbs). Heavier lighting grids, audio arrays, mid-size LED walls.
- 2-ton motor (4,000 lbs). Concert tour grids, large arrays, structural roof loads.
Critical concept: the motor's rating is the maximum load on a single pick. The total load on the rig is distributed across multiple motors, and the rigger sizes the motor count to keep each pick well within its limit. A 600-pound truss span with two motors is two 1/2-ton picks at roughly 300 pounds each — well within the motor's working limit. The same 600-pound span on one motor would be a 600-pound pick on a 1/2-ton motor, which is fine on paper but doesn't account for dynamic loading (motion, sway, audio vibration). Riggers default to two-pick spans for that reason.
Load math — the simple version
The producer-facing version of the load math is short. Three numbers matter for any flown rig:
Total dead load. The sum of the weight of everything hanging from the truss. Truss itself + lighting fixtures + audio boxes + video panels + cabling + scenic elements. The rigger adds these from a spec sheet of every component.
Dynamic factor. A safety multiplier applied to the dead load to account for motion, swing, wind (outdoor), and audio vibration. Industry standard is typically 1.5x to 2.0x depending on application. Indoor static rigs use lower factors; outdoor or motion-loaded rigs use higher.
Working load limit per pick. The motor's rated capacity divided by a safety factor. A 1/2-ton (1,000 lb) motor has a typical 4:1 safety factor, giving a working load limit of 250 lbs per pick. The rigger ensures each pick is below this number.
The rigger and engineer handle the actual calculation. The producer's job is to ask: "Have you signed off on the load math, and what's the per-pick number?" A real rigger has both answers immediately. A vendor that doesn't is a vendor to question.
The fastest way for a producer to ruin a rigging plan is to add weight to the truss mid-load-in. Bringing in an extra scenic element after the truss is in the air can put a pick over its limit before anyone re-runs the math. Tell the rigger about every flown weight on the bid. Surprises are not a feature.
ETCP — the certification that matters
ETCP stands for Entertainment Technician Certification Program, administered by ESTA (Entertainment Services and Technology Association). It's the industry-recognized certification for rigging professionals working in entertainment and event environments.
Two certifications matter:
- ETCP Rigger — Theatre. For riggers working in theatrical, ballroom, hotel, and corporate-event venues. The certification we routinely require on our LA bids.
- ETCP Rigger — Arena. For riggers working in arena, stadium, and concert tour environments. Required for tour-grade work and most major LA outdoor venues.
The ETCP certification is earned through a combination of work-hour requirements (3,000+ hours of professional rigging experience) and a proctored examination. Renewal every five years requires continuing education. An ETCP-certified rigger is the industry's baseline credential for "this person knows what they're doing with weight in the air."
For most LA corporate events, the rigging crew lead should be ETCP certified. For LA arena and stadium work, every rigger on the rig should be ETCP. For weddings and small brand activations, ETCP on the crew lead is best practice — a venue's insurance may not strictly require it, but the engineer's sign-off often does.
If a vendor pushes back on the ETCP question, escalate. The rigging crew is the line that decides whether the truss stays in the air. Cutting corners here is the corner that ends an event.
Why ETCP riggers matter — the failure mode you don't want to learn
The reason ETCP exists is that ungrounded rigging is the failure mode that ends careers. A truss that drops mid-show is not a minor incident. The certification system was built specifically to ensure the riggers handling weight over audiences have the training, the experience, and the working knowledge of failure modes to prevent the scenarios that the industry has watched happen.
What the ETCP-certified rigger knows that the uncertified rigger may not:
- How to read a venue's structural drawings. Not every beam can take a motor. Most can; some can't. The certified rigger knows the difference and knows what to ask when the drawings are unclear.
- How to compute dynamic loads under real-world conditions. Wind, vibration, motion-loaded picks, ground temperature changes that affect aluminum behavior.
- How to identify worn rigging hardware. Damaged span sets, deformed slings, motors that haven't been serviced. The 30-second walk-around that catches the catastrophic failure before it happens.
- How to call for the engineer. The certified rigger knows the line between "this is rigging" and "this needs a structural engineer's stamp."
- How to write a safe rigging plot. The drawing that the venue and the insurance company sign off on. Plots that pass have specific elements; plots that fail look incomplete to anyone who knows the format.
When to call the rigger — the producer's checklist
For producers new to flying anything: call the rigger early. The points the venue has, the load the points are rated for, and the configuration of the rig all need to be confirmed before the engineering doc on the rest of the production is locked. Late calls to the rigger are how shows discover three days before doors that the venue's points won't support the planned LED wall.
The questions worth asking the venue at the brief stage:
- What rigging points do you have, and what's each rated for? Venues that book entertainment regularly have a rigging plot showing the points and ratings. Hotels often don't.
- Who provides the engineer's stamp? Some venues require an in-house engineer's sign-off on every flown rig. Some require an outside engineer. Some have neither.
- What's the load-in window for rigging? Rigging needs its own time, separate from the rest of load-in. A two-motor flown rig is 2-3 hours of rigging-only time before the rest of the build can start.
- Are there ceiling clearance limitations? Some venues have low-clearance HVAC, sprinklers, or architectural features that limit where motors can go.
- What's the venue's labor requirement? Union venues require IATSE riggers; non-union venues let you bring your own. The labor line scales accordingly.
Scoping a flown rig? Send us the venue, the date, and what you want to fly (lighting, audio, video, scenic). Rigging plot back inside 24 hours on a business day, ETCP-certified crew built into the bid.
Send us a briefThe five truss mistakes that cost money
The patterns we see when producers handle truss without help:
Specifying truss size before the load is known. The right approach is to compile the load list first, then pick the truss to suit. Producers who pick 12-inch truss because "that's standard" sometimes discover at load-in that they needed 20-inch for the audio array weight.
Skipping the rigging plot drawing. Every flown rig should have a rigging plot — a drawing showing motor positions, truss layout, point loads, and total weight. Some vendors send invoices instead. The plot is the document the engineer signs; without it, the venue's insurance is undefined.
Underestimating motor count. A 30-foot truss span needs two motors minimum, often three for safety. Vendors who bid one motor on a 30-foot span are saving money on the bid and putting the rig at risk.
Mismatching motor capacity to load. Putting a 1-ton motor on a 200-pound load is fine. Putting a 1/2-ton motor on a 600-pound load is over the working limit. The motor selection should match the actual load.
Treating rigging as a same-day add-on. Riggers need to walk the venue, confirm the points, and pre-rig the rig before show day. A rigger called in the morning of the event is a rigger making decisions under time pressure.
Where we go from here
Truss is structural. Structural decisions have structural consequences. Producers who treat the rigging line as something to negotiate down have not learned what's underneath the bid; producers who treat it as the load-bearing line on the entire engineering doc are the ones whose events stay in the air.
If you're scoping anything flown — lighting, audio, video, scenic, brand build — send a short brief. The venue, the date, the load list, and a sentence on the look. Our LA dispatch covers every working venue with ETCP-certified riggers — DTLA, Hollywood, Burbank, Beverly Hills, Santa Monica, and Pasadena. Rigging plot back inside 24 hours on a business day.
The rig is engineered to the load. The load is engineered to the show. The show is engineered to the room. That's the order, every time.