Lifting Equipment Testing Methods Quiz

Units of Measure

• A unit of measure is a standardized quantity of a physical property used to determine multiple quantities of the same property.
• Examples include weight, length, mass, and force.
• Different systems of units are based on fundamental units.
• The International System of Units (SI) is the most widely used system, with seven base units.
• Other SI units can be derived from these base units.
• When marking lifting equipment using the SI system, fractions of a tonne (e.g., 2.1t) are typically marked with one decimal place except for 0.25, which is marked using two decimal places (e.g., 2.25t).

Symbols and Conversions

• Ton (US): T = Imperial/US Ton = 2,000 lbs = 907.185 kg
• Ton (metric): t = metric tonne = 1,000 kg = 2,204.62 lbs
• Ton (Imperial): 1 Ton (imperial) = 1,016 kg = 2,239.9lbs
• Hundredweight (cwt): 1 cwt = 50 kg

Other Useful Conversions

• 1 kg = 2.2 lbs
• 1 inch = 25.4 mm
• 1 foot = 12 inches
• 10 kN = 1,000 kg (approximately)

Test Machines and Force/Load Measuring Equipment

• Accuracy is essential when applying load or force, as stipulated by many product standards and codes of practice.
• The LEEA Technical Requirements for Members and Guidance document lists the accuracy requirements and intervals for calibrating test machines and load cells as per ISO7500-1.
• ISO7500-1 has various classes/grades of machines relating directly to accuracy (e.g., Grade 0.5 = ±0.5%, 1.0 = ±1%, 2.0 = ±2%).
• Calibration certificates specify the Lower Limit of Calibration (load/force) below which accurate values cannot be measured.

Dimensional Measuring Equipment

• The most basic equipment used for lifting equipment verification is graduated to national standards in 1mm increments.
• More precise equipment, such as a Vernier gauge (0.1 mm graduation), may be needed for certain items.

Crack Detection

• For general lifting equipment, basic crack detection (dye penetration or magnetic particle) is common.
• Trained operatives perform and interpret the results.
• More detailed crack detection methods (eddy current, radiography, ultrasonic) are used for high-value items with stringent safety requirements.

Dye Penetrant, Magnetic Particle, Eddy Current, and Radiography

• Different methods for detecting surface cracks/defects in materials
• Dye penetrant: detects surface breaks in nonporous material
• Magnetic particle (MPI): detects surface cracks in ferrous/magnetic materials
• Eddy current: detects surface and subsurface anomalies in conductive materials
• Radiography: detects internal and surface defects using radiation

Ultrasonic

• High-frequency sound waves used to detect cracks in a material.
• Speed, reliability, and versatility

Electromagnetic Wire Rope Examination

• Fast method for detecting defects in long wire ropes using magnetic flux and leakage methods

Hardness (Vickers, Brinell, Rockwell)

• Indentations used for verification of lifting equipment hardness.
• Measurement of material's resistance to indentation
• Brinell is the most common method in the lifting equipment industry.

Impact Tests (Charpy, Izod)

• Measures energy absorbed by a material during fracture to determine its notch toughness.
• Identifies a material's properties when experiencing shock loading.
• Used to evaluate weld quality, identifying potential defects or weaknesses.

Marking Lifting Equipment

• Equipment should be marked permanently (e.g., plates, metal tabs, labels) in an appropriate, non-load-bearing location.
• Marking should conform to relevant standards for location, size, and information conveyed.

Trigonometry of Slinging

• Multi-leg slings at angles increase load in individual legs according to trigonometry.
• Best practice is to measure the angle between the sling leg and the vertical
• Included angles, angles to the vertical, and angles to the horizontal may be used

Uniform Load Method

• Simpler rating method used for multi-leg slings and is easier to calculate.
• Rating based on included angle and leg count/single leg WLL
• Recommended for multipurpose slings
• Multi-purpose 4-leg sling rated same WLL as 3-legged sling (assuming 3 legs carry the load).

Trigonometric Method

• Accounts for varying angle to vertical.
• Sling capacity depends on the angle between the lifting sling legs and the vertical.
• Operative must calculate angle and adjust rating accordingly for all multiple-leg sling scenarios.
• Uniform Load Method is often used for simplicity but the trigonometric method may be used for unique purposes.

Multi-leg Sling User Information

• Rating reduced if fewer legs are used to lift the load.
• Reduced rating is based on the actual number of legs used to perform the lift.