Building Regs in your pocket. Calculators on your site.
Ask Siri.
Get Answers.
Voice-powered building regulations, cable sizing calculators, and fault-finding guides — all running offline on your iPhone. Your hands are dirty, you're up a ladder, and you need to check a regulation. Just ask.
£14.99 one-time · No subscription · No data collected
“Hey Siri, ask
Auvi Trade…”
Your hands are covered in grease. You're holding a cable. You're wedged in a ceiling void. Just talk. Siri routes your question to Auvi Trade, which answers from the Approved Documents — completely hands-free, completely offline.
- Voice-activated — no need to touch the screen
- Works in airplane mode — no internet needed
- Answers in seconds from on-device models
- References regulation numbers in every answer
Hands-Free
Regulation Answers.
Type or speak your question — Auvi Trade searches the Approved Documents and explains the answer in plain English, with the regulation reference so you can quote it to Building Control.
- WhisperKit speech recognition — entirely on-device
- Plain-English answers with regulation references
- Works for electricians, plumbers, and gas engineers
Cable Sizing.
From First Principles.
Every calculator is derived from physics and engineering — conductor resistivity, cross-sectional area, thermal limits, and installation methods. Not copied tables. This means calculations are always based on verifiable science, not someone else's intellectual property.
- Cable current capacity from conductor physics
- Voltage drop: V = I × R × L (Ohm's law)
- Zs = Ze + (R1 + R2) with pass/fail indication
- Maximum demand, pipe sizing, gas pipe sizing, heat loss
Every Approved Document.
In Your Pocket.
Full text of Parts P, G, J, B, and L — searchable, indexed, and cross-referenced. Published by HM Government under the Open Government Licence v3.0. No need to carry the books on site.
- Part P — Electrical Safety in Dwellings
- Part G — Sanitation, Hot Water Safety
- Part J — Combustion Appliances & Fuel Storage
- Parts B & L — Fire Safety, Energy Conservation
- Full-text search across all documents
No Data Collected.
No Exceptions.
Same privacy philosophy as Auvi. Everything runs on your device. No accounts, no analytics, no tracking, no cloud. Apple verified: “No Data Collected.” Your calculations, your questions, your job sites — all stay on your phone.
- Works in airplane mode — everything on-device
- No sign-up, no account, no email required
- Your job site data stays on your device, always
Three Steps. On Any Job.
Download
Install Auvi Trade from the App Store. A one-time download prepares all reference content and on-device models — about 500 MB.
Ask a Question
“Hey Siri, ask Auvi Trade…” or type your question. Voice works when your hands are dirty, wet, or gloved.
Get the Answer
Plain-English answer with the regulation reference. Run a calculation, browse the Approved Documents, or check a decision tree.
Built for the Job Site.
Calculators, decision trees, visual references, and fault-finding guides — all offline, all in one app.
“Is this work notifiable?” — interactive flowchart tells you in seconds
ElectricalInteractive zone diagram with IP ratings and permitted equipment
ElectricalSupply assessment, cable design, earthing, testing, smart charger requirements
ElectricalCable and pipe penetration requirements for fire-separating elements
All TradesGuided flowcharts for RCD tripping, no power, partial loss of supply
ElectricalEarth conductor sizing using the adiabatic equation
ElectricalLoading units method for domestic hot and cold water systems
PlumbingPressure drop method for domestic gas installations
GasRoom-by-room heat loss for heating system design
Gas / HeatingSave calculations, export results, keep records of your work
All TradesUpdated for BS 7671 Amendment 4 (April 2026) — batteries, PoE, ICT earthing
ElectricalEverything works without internet. Basements, voids, building sites — no signal needed
All TradesLess Than a Coffee Round.
Reference books cost a fortune and stay on the shelf. Competitor apps charge subscriptions. Auvi Trade is a one-time purchase you carry everywhere.
| Resource | Cost | Type | Portable |
|---|---|---|---|
| BS 7671 (18th Ed.) | £90 | Book | Heavy |
| IET On-Site Guide | £40 | Book | |
| IET Wiring Matters App | £35/yr | Subscription | Phone |
| Day rate lost to looking things up | £200–400 | Time | — |
| Auvi Trade | £14.99 | One-time | Always with you |
Auvi Trade does not reproduce BS 7671 or IET publication content. Calculations are from first principles; reference content is from Approved Documents (Crown Copyright, OGL v3.0).
Works Where You Do.
On a Ladder
Voice-activated — no need to climb down
In a Ceiling Void
Works offline, even where the Wi-Fi doesn't reach
At the Consumer Unit
Quick cable sizing and Zs checks on site
On a Gas Job
Pipe sizing and flue clearance checks instantly
In the Van
Check regulations before you start the job
During an Inspection
Quote the exact regulation to Building Control
One Price. Everything Included.
No subscription. No tiers. No in-app purchases. Every feature, every calculator, every Approved Document — one payment, forever.
Auvi Trade
Pay once, use forever. All updates included.
No subscription- Siri integration — hands-free voice Q&A
- All calculators (cable sizing, voltage drop, Zs, max demand, pipe sizing, gas pipe, heat loss)
- Searchable Approved Documents (Parts P, G, J, B, L)
- Part P notifiable work decision tree
- Bathroom zones interactive diagram
- EV charger installation checklist
- Fire stopping reference (Part B)
- Fault-finding guided flowcharts
- CPC sizing (adiabatic equation)
- Save & export calculations
- 100% offline — no internet needed
- No data collected. Ever.
- BS 7671 Amendment 4 ready (April 2026)
Price shown in GBP. App Store price may vary by region. All purchases through Apple.
Building Regs. In Your Pocket.
Auvi Trade is coming soon to the App Store. One-time purchase, no subscription, no data collected. Built for UK tradespeople who need answers on site.
Coming Soon to the App StoreRequires iPhone or iPad · iOS 17 or later · £14.99 one-time