Document ID: chunk:federal_register_of_legislation:F2021L01869:reg:6:p75
Version: federal_register_of_legislation:F2021L01869
Segment Type: reg
Provision Reference: reg 6 (pt 75/86)
Character Range: 256561–262066

applications in examining heritage fabric.   Locating decay, fractures and structural weakness in timber; assessing extent of decay on the surface of timber; checking fault planes and zones of weakness in stone; establishing depth of surface cracks, weathering decay or fire damage; verifying the effectiveness of consolidation and repair and the bond between individual stones.   Quick; reliable; inexpensive; can be used on very fragile stone or painted surfaces.                                                                            Access to opposing sides of material being tested can be a major limitation; high level of expertise required to interpret results; cannot be used where there are a number of discontinuities such as across a random rubble wall.
Moisture measurement   Technique using electrical resistance meters.                                                                         Measures moisture content on or just below the surface of building material.                                                                                                                                                                                                                                                                    Cost-effective; widely used.                                                                                                                                    Information can be inaccurate and of little value; more serious problems may remain hidden; false readings possible from salts in brickwork, foil behind plasterboard, high
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             carbon content, condensation or

TECHNIQUE   DESCRIPTION   APPLICATIONS   ADVANTAGES   DISADVANTAGES
                                                      old surface treatments.

   b.  Destructive techniques

  Destructive investigative techniques must:

      * be approved by the Actions Committee as no destructive techniques are permitted actions

      * only be considered after other forms of non-destructive techniques have failed to provide the required information

      * be undertaken by a conservator or otherwise skilled practitioner

      * be carried out in areas that are visually discreet, such as loose or previously altered decorative surfaces, above false ceilings, under raised floorboards, under easily temporarily moved hardware

      * include documentation of the 'before and after' condition of the affected heritage fabric.

TECHNIQUE                                DESCRIPTION                                                                                                                                                                        APPLICATIONS                                                                                                                                                                    ADVANTAGES                                                                                                                                         DISADVANTAGES
Endoscopy                                Equipment attached to a tube inserted by drill to 12 mm into a material.                                                                                                           Inspecting voids under floors or behind panelling; revealing hidden problems such as fungal growth.                                                                             Equipment is flexible and can be steered by inbuilt wires; possible to attach still or video camera to record findings; can record down to 2 mm.   Equipment is sophisticated and expensive; difficult to retain scale of image observed and manipulate the direction of the tip.
Micro-drilling                           Very accurate method for assessing faults and variations due to decay and other defects of timber by drilling in a probe linked to a computer up to 200 mm, leaving a 1 mm hole.   Measuring severity of decay; calculating ratio of decayed timber to sound timber; assessing structural integrity; assessing condition behind surface and decorative finishes.  Easily interpreted information compared with other techniques, although still requires a skilled practitioner.                                     Should be used in conjunction with ultrasound to allow for innate differences in softness of timber types.
Laboratory analysis – paint              Identifying paint types and colours.                                                                                                                                               Recreation of heritage colour schemes.                                                                                                                                          High level of magnification capable of ascertaining subtleties between various layers including prime coats.                                       Destruction