1. Safety and sharp metal
Cut edges, overhead drilling, grinder sparks, lift movement, pinch points, and falling hardware are day-one problems.
What do you need right now?
This page is only a starting map. Pick one path and move. You do not need to browse the whole site first.
I’m stuck right now
Duct not level, damper access blocked, flex sagging, TDC won’t line up, or you are about to cut/drill/reroute.
Open Field Rescue →
I need the basics
Airflow, BOD/TOD, gridlines, duct sizes, hangers, S-and-drive, TDC, VAVs, TAB, and clean foreman questions.
Open Core Basics →
I don’t know what this is
Start visually: rectangular duct, spiral, supports, dampers, flex, finish work, access panels, and red-zone items.
Open Photo ID →
I want to learn by year
200 apprentice questions organized from 1st-year basics through 4th-year pre-foreman work.
Open Learn Q&A →
I need to ask clean
Use a short script so your foreman hears the actual field problem, what you checked, and what decision you need.
Open Ask Foreman →
What a new apprentice should learn first
Before you worry about every code detail, get fluent in the basics that show up every day.
2. What air is doing
Know supply, return, exhaust, outside air, relief air, and why duct size and restrictions matter.
3. Measurements and elevations
BOD, TOD, centerline, gridlines, benchmarks, hanger points, and “field verify” are the language of layout.
4. Assembly names
Learn S-and-drive, Pittsburgh, TDC/TDF, Ductmate, spiral couplings, flex collars, boots, taps, and transitions.
5. Supports before duct
Hanger rods, strut, trapeze, strap, anchors, rod length, level, plumb, and spacing make the run behave.
6. Access and finish work
Dampers, VAV controls, filters, cleanouts, diffusers, grilles, and ceiling tile work all need access and clean finish.
How to use TinnerFlow without getting buried
Use the site like a field decision tool, not a textbook you have to read front to back.
Search in plain jobsite words.
Try “duct not level,” “flex sagging,” “damper access blocked,” “what is BOD,” or “TDC won’t line up.”
Read the risk level first.
Red means stop and verify. Yellow means check before moving on. Green means basic reference. Blue means coordinate.
Use the checklist before acting.
Most mistakes happen when the apprentice skips the simple checks: print, elevation, support, access, direction, clearance, and connection type.
Ask the foreman with context.
Say where you are, what you see, what you already checked, and what decision you need. That is the whole Ask Foreman layer.
Quick Field Rescue search
Type the problem like you would say it on a lift.
Red-zone rule: ask before you touch it
These are not “figure it out” items. TinnerFlow can help you recognize the risk and ask better, but it does not approve the work.
Fire / smoke dampers
Access, sleeve, retaining angles, actuator clearance, breakaway joints, rated walls, and inspection requirements.
Grease duct
Kitchen exhaust, welded duct, clearance, fire wrap, cleanouts, slope, and liquid-tight inspection issues.
Seismic / structure
Bracing, shafts, anchors, post-tension slabs, beams, structural attachments, and engineered support details.
Rigging / crane lifts
RTUs, curb adapters, tag lines, wind, load paths, signal person, lift director, and fall zones.
Cutting / drilling / coring
Rated assemblies, hidden utilities, PT cables, structural steel, roof openings, and anything that changes the building.
Major field modifications
Reroutes, resized duct, VAV location changes, roof curb mismatch, TAB-impacting changes, and inspection fixes.
The simple rule
TinnerFlow helps you identify, check, and ask. The approved drawings, specifications, manufacturer instructions, employer safety rules, foreman, inspector, engineer, and AHJ always control the actual work.