4.4 Ground vibration limits

Frequency-dependent limits have the capacity to precisely deal with the hazards presented by ground vibration and are seen as the basis for best practice blasting. The particular frequency-dependent criteria should be reported with the measurements. All the limits given in this section are peak component particle velocities, as used in overseas standards and guidelines. The classification of type of structure may be difficult; when in doubt, a more conservative limit from the nearest description in the structural damage table should be applied.

4.4.1 Human comfort limits

Because the human response to vibration depends on a range of factors, such as vibration levels, location and time of day, different statutory requirements for human comfort limits for ground vibration may apply in different jurisdictions.

General guidance on human response to building vibrations is given in AS 2670.2–1990 Evaluation of human exposure to whole-body vibration—continuous and shock-induced vibration in buildings (1 to 80 Hz), ISO 2631–2:2003 Mechanical vibration and shock— evaluation of human exposure to whole body vibration—Part 2: Vibration in buildings (1 Hz to 80 Hz), BS 6472 –1:2008 Guide to evaluation of human exposure to vibration in buildings. Vibration sources other than blasting, and BS 6472–2: 2008 Blast-induced vibration. A typical set of limit criteria for human comfort is shown in Table 4.1.

Table 4.1 Ground vibration limits for human comfort (blasting)
​Blasting​​
​Category ​Type of operations ​Peak component particle velocity (mm/s)
Sensitive site*​ ​Operations lasting longer than 12 months or more than 20 blasts

​5 mm/s for 95 per cent blasts per year

10 mm/s maximum unless agreement is reached with the occupier that a higher limit may apply

Sensitive site​*​ ​Operations lasting for less than 12 months or less than 20 blasts ​10 mm/s maximum unless agreement is reached with the occupier that a higher limit may apply
Occupied non-sensitive sites, such as factories and commercial planes​ All blasting​ 25 mm/s maximum unless agreement is reached with the occupier that a higher limit may apply for sites containing equipment sensitive to vibration, the vibration should be kept below manufacturer's specifications or levels that can be shown to adversely affect the equipment operation​
Table 4.1 (cont.) Ground vibration limits for human comfort (other)
​Other​​
​Category ​Period ​Peak component particle velocity (mm/s)
​Residential ​Night-time ​0.2 mm/s
Daytime​ 0.3 mm/s​ mm/s​
​Offices ​When occupied 0.6 mm/s​
​Occupied non-sensitive sites, such as factories and commercial premises When occupied​ ​2.5 mm/s

mm/s = millimetres per second
a A ‘sensitive site’ includes houses and low-rise residential buildings,
theatres, schools, and other similar buildings occupied by people.

4.4.2 Building damage limits

Currently there exists no Australian Standard for assessment of building damage caused by vibrational energy. This section summarises the most relevant available standards from the United Kingdom, the United States and Germany.

Frequency-independent and frequency-dependent guide levels are described in both British Standard BS 7385–2: 1993 Evaluation and measurement for vibration in buildings.

Guide to damage levels from groundborne vibration and the United States Bureau of Mines (USBM) RI 8507 Impacts to structures. The levels specified are peak component particle velocities, and the methods used for assessing the frequencies are similar in both documents.

Frequency-dependent criteria are important for assessing the blast-induced vibration effects on buildings and other structures and are the recommended approach. Frequency-dependent criteria may not be readily implemented for all applications.

For blasting operators who do not have the facilities to use frequency-dependent assessment methods, the levels specified in Table 4.3, which are more conservative for most blasting applications, will reduce the potential for damage. The table should be used in conjunction with the notes.

Wherever possible, the ground vibration levels from all blasting operations must be limited to the damage limit criteria shown below at all sites not in the ownership or control of the organisation commissioning the blasting.

Table 4.2 BS 7385-2 Transient vibration guide values for cosmetic damage
​Line Type of building​ ​Peak component particle velocity in frequency range of predominant pulse
​4 Hz to 15 Hz 15 Hz and above​​
1​ ​Reinforced or framed structures. Industrial and heavy commercial buildings 50 mm/s at 4 Hz and above​
​2 Unreinforced or light framed structure. Residential or light commercial type buildings​ 15 mm/s at 4 Hz increasing to 20 mm/s at 15 Hz​ 20 mm/s at 15 Hz increasing to 50 mm/s at 40 Hz and above​

Notes:
1 Values referred to are at the base of the building.
2 For line 2, at frequencies below 4 Hz, a maximum displacement of 0.6 mm (zero to peak) should not be exceeded.

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Table 4.3 BS 7385-1:1990-Damage Classification
​Damage classification ​Description
​Cosmetic ​The formation of hairline cracks on drywall surfaces or the growth of existing cracks in plaster or drywall surfaces; in addition, the formation of hairline cracks in the mortar joints of brick/concrete block construction
​Minor ​The formation of cracks or loosening and falling of plaster or drywall surfaces, or cracks through bricks/concrete blocks
​Major ​Damage to structural elements of the building, cracks in support columns, loosening of joints, splaying of masonry cracks etc.
Table 4.3 (cont.) SBM Damage Classification​
​USBM Damage Classification​
​Uniform classification Description​
Threshold​​ ​Loosening of paint; small plaster crack at joints between construction elements; lengthening of old cracks
Minor​ ​Loosening and falling of plaster; cracks in masonry around openings near partitions; hairline to 3 mm cracks (0 to 1/8 in); fall of loose mortar
​Major ​Cracks of several mm in walls; rupture of opening vaults; structural weakening; fall of masonry, e.g., chimneys; load support ability effected

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USBM 'Safe' blasting vibration level criteria.

Research suggests that the guide values and assessment methods given in BS 7385–2 and (USBM) RI 8507 are applicable to Australian conditions, and are recommended for explosives users with the facilities to make use of them. The estimation of the frequency of each vibration component to be used in structural damage assessment is complex. Simple approaches suggested within the BS 7385–2 and (USBM) RI 8507 include:

  • frequency of the maximum peak particle velocity amplitude peak
  • dominant frequency of the component vibration time history
  • zero crossing frequency of the peak particle velocity amplitude peak.

The (USBM) RI 8507 and BS 7385–2 methods for assessing frequencies have been widely used for many years, and were suitable for use with desktop and laptop computers with the power that was commonly available in the 1980s and early 1990s. It appears that the motion frequencies determined by simple methods, such as zero crossing, are conservative for assessing damage potential.

German Standard DIN 4150–3:1999–02 Vibration in buildings—Part 3: effects on structures provides recommended maximum levels of vibration that reduce the likelihood of building damage caused by vibration. These levels are ‘safe limits’, up to which no damage due to vibration effects have been observed for the particular class of building. ‘Damage’ is defined by DIN 4150 to include even minor non-structural effects such as superficial cracking in cement render, the enlargement of cracks already present, and the separation of partitions or intermediate walls from load bearing walls. If such damage is observed without vibration exceeding the ‘safe limits’ it can be attributed to other causes. DIN 4150 also states that when vibrations higher than the ‘safe limits’ are present, it does not necessarily follow that damage will occur.

Table 4.4 Vibration standards for buildings, DIN 4150–3
​Group Type of structure​ Peak vibration velocity, mm/s​
​At foundation at a frequency of Plane of uppermost storey​
​Less than 10 Hz 10 Hz to 50 Hz​ to 100 Hz​ to 100 Hz​ All frequencies​
1​ ​Buildings used for commercial purposes, industrial buildings and buildings of similar design ​20 ​20 to 40 ​40 to 50 ​40
​2 Dwellings and buildings of similar design and/or use​ ​5 ​5 to 15 ​15 to 20 ​15
​3 Structures that because of their particular sensitivity to vibration, do not correspond to those listed in Lines 1 or 2 and have intrinsic value (e.g. buildings that are under a preservation order)​ ​3 ​2 to 8 ​8 to 10 ​8

Source: DIN 4150–3:1999–02 Vibration in buildings—Part 3: effects on structures

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