Elcometer 309 Delta T Hygrometer

Real use-case: On UAE tank, pipeline, and structural steel coating jobs, inspectors grab the Elcometer 309 Delta T Hygrometer for a clear go/no-go before the spray gun starts — so dewpoint and humidity don’t kill adhesion in coastal heat and night shifts.

Most reseller pages just paste Elcometer’s brochure. This page is written for buyers who need to know when to paint, not only the model number.

Why Delta T and RH matter before coating

Paint data sheets almost always call out two climate limits: Delta T (surface temperature minus dewpoint) and relative humidity. If Delta T drops under about 3°C (5°F), moisture can sit on the steel and the coating can fail. RH limits are often 75–85%. The 309 is built to read those two checks fast and show pass/fail on site.

What the Elcometer 309 gives you on site

• Delta T preset above the industry 3°C threshold, with on-screen tick/cross and red/green LEDs
• RH 0–100% (±3%), user-set upper limit (default 75%)
• Surface/air temperature range roughly −20°C to +80°C, 0.1° / 0.1% RH resolution
• Hold/release to freeze a reading for the log sheet
• Backlight for tanks, scaffolds, and night work
• Waterproof / dustproof body with sealed sensors
• Power: 2× AA or USB; 40+ hours typical with backlight off
• Aligns with common dewpoint practice under ISO 8502-4 and BS 7079-B4

Kit (typical — G309—-1)

Elcometer 309 Delta T Hygrometer, wrist strap, 2× AA batteries, protective pouch with belt clip, RH probe calibration certificate, operating instructions.

309 vs Elcometer 319

Choose the 309 for fast spot checks and a hard pass/fail on Delta T + RH. Step up to the Elcometer 319 when you need full climatic logging, stats, and Bluetooth/USB records for ITPs and client packs.

Shop the category + related guide

Browse all thermohygrometers at MME UAE, and for a related humidity/dewpoint field workflow see How to Use the Testo 605i Thermohygrometer for HVAC Professionals.

Need a quote, rental, or calibration support in Dubai? Call MME — Deira head office and showroom stock measuring instruments for coating and industrial crews across the UAE.