Theoretical stack-effect draft
API · /chimney-api
Chimney & Flue API
Chimney and flue sizing maths as an API, computed locally and deterministically — the draft and dimension numbers a stove installer, sweep or builder runs so a fire pulls cleanly and safely. The flue-size endpoint gives the minimum flue cross-section for a fireplace opening: at least a tenth of the opening area for a square or rectangular liner, a twelfth for a round one (which draws better) — a 36 × 30 inch opening needs about 108 square inches of rectangular flue, or a 10.7-inch round. The draft endpoint gives the theoretical draft from the stack effect, ΔP ≈ 3465 × height × (1/T_outside − 1/T_flue) with temperatures in kelvin, so a 6-metre chimney with 200 °C flue gas on a freezing day pulls about 32 pascals (0.13 inches of water column) — taller and hotter draws harder. The height endpoint applies the 3-2-10 rule: a chimney must finish at least 3 feet above where it pierces the roof and at least 2 feet above anything within 10 feet, whichever is higher. Everything is computed locally and deterministically, so it is instant and private. Ideal for hearth and stove-installer apps, chimney-sweep and inspection tools, building-design calculators, and DIY-safety sites. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. Educational estimates — verify against your appliance listing and adopted code.
API health
healthy- Uptime
- 100.00%
- Server probes · 24h
- Avg latency
- 81 ms
- Server probes · 24h
- Subscribers
- 3,284
- active
- Total calls
- 4
- last 7 days
Pricing
Pick a tier — billed monthly, cancel anytime.
Free
Free
- 420 calls / month
- 2 requests / second
- Hard cap (429 above quota, no overage)
- 420 calls/month
- 2 req/sec
- Flue size + draft + height
- No credit card
Starter
€5.25 /month
- 11,000 calls / month
- 6 requests / second
- Hard cap (429 above quota, no overage)
- 11,000 calls/month
- 6 req/sec
- Stack-effect draft
- Email support
Pro
€17.20 /month
- 72,000 calls / month
- 15 requests / second
- Hard cap (429 above quota, no overage)
- 72,000 calls/month
- 15 req/sec
- Installer & inspection pipelines
- Priority support
Mega
€51.60 /month
- 245,000 calls / month
- 36 requests / second
- Hard cap (429 above quota, no overage)
- 245,000 calls/month
- 36 req/sec
- Platform scale
- Dedicated SLA
Built by
Related APIs
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Industrial Coatings API
Industrial and protective-coatings maths as an API, computed locally and deterministically — the film-build numbers a coatings inspector, painter or estimator works to, the ones simple paint estimating skips. The coverage endpoint gives theoretical and practical coverage from the coating's volume solids and the target dry film thickness: coverage = 1604 × the volume-solids fraction ÷ the DFT in mils, where 1604 is the square feet a gallon covers at one mil — so a 50 %-solids coating at 2 mils dry covers about 401 ft² per gallon, less a loss factor for overspray and surface profile. The film-thickness endpoint converts between wet and dry film thickness through the volume solids: WFT = DFT ÷ the solids fraction, because the solvent flashes off and the film shrinks, so a 50 %-solids coating laid 4 mils wet dries to 2 mils — the number you check with a wet-film comb as you spray. The transfer-efficiency endpoint gives the real material needed: theoretical gallons ÷ the transfer efficiency, since conventional spray lands only ~25 % on the part, HVLP ~65 %, electrostatic up to ~95 %. Everything is computed locally and deterministically, so it is instant and private. Ideal for coatings-estimating and inspection apps, industrial-painting and protective-coating tools, NACE/SSPC study aids, and spec calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. For simple wall-paint area estimating use a paint API.
api.oanor.com/coating-api
HVAC Ductwork API
HVAC duct-sizing maths as an API, computed locally and deterministically — the duct dimensions an installer or designer sizes a system with so the air moves quietly and efficiently. The round-duct endpoint gives the round duct for an airflow at a target velocity: area = airflow ÷ velocity (CFM ÷ ft/min = ft²), then diameter = √(4·area/π) — 400 CFM at a 700 fpm trunk velocity wants about a 10.2-inch round, rounded up to the next 12-inch trade size. The velocity endpoint gives the air speed inside a duct from the airflow and its size, round or rectangular — 400 CFM through a 12 × 8 duct runs at 600 fpm, comfortably quiet, while the same air in a 10-inch round moves at 733 fpm. The equivalent endpoint gives the equivalent round diameter of a rectangular duct by the ASHRAE relation De = 1.30 · (a·b)^0.625 ÷ (a+b)^0.25, so a 12 × 8 rectangular carries the same air at the same friction as a 10.7-inch round — letting you size on a round friction chart and convert to fit the space. Everything is computed locally and deterministically, so it is instant and private. Ideal for HVAC-design and installer apps, duct-sizing and takeoff tools, building-services calculators, and trade-school aids. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. For room air changes use a ventilation API; for the cooling/heating load use an HVAC API.
api.oanor.com/ductwork-api
Plumbing Code API
Plumbing-code sizing maths as an API, computed locally and deterministically — the fixture-unit and pipe-sizing numbers a plumber, designer or inspector runs from the code book. The dfu endpoint totals drainage fixture units for a set of fixtures (IPC Table 709.1): pass a list like toilet:2,lavatory:3,shower:1,kitchen_sink:1 and it weights each by its discharge — a toilet is 3, a lavatory 1, a tub or shower 2 — for a total of 13, with a grouped full bathroom counting as 6 rather than the sum of its parts. The pipe-size endpoint gives the minimum building-drain size for a DFU load at a slope (IPC Table 710.1(1)): the smallest pipe whose capacity meets the load, so 50 DFU at a quarter-inch-per-foot fall needs a 4-inch drain, with the reminder that any drain carrying a water closet is a 3-inch minimum. The supply-gpm endpoint reads probable peak water demand off the Hunter curve: diversity means 100 supply fixture units draws only about 54 GPM, not the sum of every fixture running at once — the number you size the water service against. Everything is computed locally and deterministically, so it is instant and private. Ideal for plumbing-design and estimating apps, code-check and permit tools, MEP-engineering calculators, and trade-school aids. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. Based on the IPC — verify against the code adopted in your jurisdiction.
api.oanor.com/plumbing-api
Caulk Coverage API
Caulk and sealant coverage maths as an API, computed locally and deterministically — the linear-feet-per-tube and how-many-tubes numbers a builder, glazier or DIYer buys sealant by. A bead of caulk is essentially a thin cylinder, so the coverage endpoint works out the feet a cartridge lays from the bead width: volume per foot ≈ (π/4 × width²) × 12 inches, and a standard 10.1 fl oz cartridge (18.2 in³) lays about 30 feet of a quarter-inch bead, 13 feet of a fat three-eighths or 55 of a fine three-sixteenths — pass cartridge_oz for sausage packs or 28-oz tubes, and a tube count to total it. The tubes endpoint runs it backwards: cartridges needed = (joint length × a waste factor) ÷ feet per cartridge, rounded up, so a 100-foot run of quarter-inch bead with 10 % waste takes four tubes. Everything is computed locally and deterministically, so it is instant and private. Ideal for construction, glazing, weatherproofing and home-improvement app developers, material-estimator and shopping-list tools, and contractor software. Pure local computation — no key, no third-party service, instant. Inches and feet; estimates — tooling and waste vary. Live, nothing stored. 2 compute endpoints.
api.oanor.com/caulk-api
Frequently asked questions
Quick answers about pricing, quotas, and integration.
How do I get an API key for Chimney & Flue API?
What's the rate limit for Chimney & Flue API?
How much does Chimney & Flue API cost?
Can I cancel my subscription anytime?
Is Chimney & Flue API GDPR-compliant?
Pick an endpoint from the list on the left to see its details and try it.
Code snippets
Sign up to get an API key, then call any path under your slug.
curl https://api.oanor.com/chimney-api/SOME_PATH \
-H "x-oanor-key: oanor_test_..."
const res = await fetch("https://api.oanor.com/chimney-api/SOME_PATH", {
headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();
$ch = curl_init("https://api.oanor.com/chimney-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);
import requests
r = requests.get(
"https://api.oanor.com/chimney-api/SOME_PATH",
headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())
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