IS 6922:1973 is the Indian Standard (BIS) for criteria for safety and design of structures subject to underground blasts. This standard provides criteria for the safety and design of structures subjected to ground vibrations from underground blasts. It establishes damage thresholds based on Peak Particle Velocity (PPV) for different types of structures and outlines methods to predict vibration levels from blasting operations.
Criteria for safety and design of structures subject to underground blasts
| Parameter | IS Value | International | Source |
|---|---|---|---|
| PPV Limit for Residential Structures | 5-12 mm/s, depending on building type and foundation. It is not frequency-dependent. | Varies with frequency, e.g., 5 mm/s below 10 Hz, ramping up to 20 mm/s between 10-50 Hz. | DIN 4150-3 |
| Frequency Dependency of Limits | Not explicitly defined; provides fixed PPV values. | Explicitly defined; a graphical chart or tiered system where allowable PPV increases with frequency. | USBM RI 8507 |
| PPV Limit for Historical/Sensitive Structures | 2 mm/s (on rock/soil) | 3 mm/s (for frequencies <10 Hz) to 10 mm/s (for frequencies 50-100 Hz) | DIN 4150-3 |
| Default Scaled Distance Formula Basis | Primarily uses square root scaling (Charge Weight^0.5). | Often uses or refers to cube root scaling (Charge Weight^0.33) as a common alternative, while emphasizing site-specific regression analysis. | General practice, e.g., AS 2187.2 |
| Airblast Overpressure Limit | Not specified. | 115 dBL (general recommended limit for sensitive areas). | AS 2187.2-2006 |
| Damage Threshold for Cosmetic Cracks | Implicit in the PPV limits (e.g., exceeding 8-12 mm/s for houses may cause damage). | Guide value is 15 mm/s at 4 Hz, increasing to 50 mm/s at 40 Hz and above for intermittent vibration. | BS 7385-2 |