G1.5 Gauge

Technical Specifications

Overview of the G1.5 Crack Gauge

The G1.5 crack monitor is a precision device designed for tracking and monitoring crack width variations. It stands out for its carbon construction and its 0.02 mm resolution.

Carbon offers two key benefits:

1. a very low thermal expansion coefficient (3.5 × 10⁻⁶), eliminating temperature-induced measurement bias
2. a corrosion-resistant material ensuring increased durability

Thanks to its design, the G1.5 gauge is reusable. The 0.02 mm resolution enables highly accurate movement tracking. Readings are taken using a vernier principle, as with all models in the G1 family.

The crack monitor consists of two carbon rules sliding within PA12 Nylon clips—a polyamide known for its excellent dimensional stability and high weather resistance. Markings are pad printed and UV-resistant.

The G1.5 gauge is supplied with impact anchors for mechanical fastening. It features two Ø 4 mm holes for installation. Fastening is done through the device (the anchor’s shoulder overlaps the crack monitor).

Each G1.5 device has a unique ID in QR format, enabling tracking via the free application available at https://saugnac.app. The app allows:
recording and archiving of measurements and photos, viewing their evolution as graphs, and reassigning the crack monitor for use on a new site with a new monitoring cycle.

Reading Principle

Use the provided magnifier to read the measurement. The upper scale, graduated from 0 to 100 mm, represents the main measurement scale. The lower scale corresponds to the vernier. Reading method:

1. Identify the main scale graduation immediately to the left of the vernier zero. This value gives the whole millimeters.
2. Find the vernier mark that aligns exactly with a main scale mark. This indicates the decimal part to add.

Examples:

1) Reading an exact value: 34 mm – The vernier zero aligns exactly with a millimeter division.
2) Reading 0.02 mm precision: 25.64 mm – The vernier zero lies between two millimeter divisions. The division to the left shows the whole millimeters: 25 mm – Vernier mark 64 (highlighted by the blue arrow) aligns with a mark on the main scale. Add 64 hundredths.