BS EN 17488 pdf free download
BS EN 17488-2021 pdf free download.Conservation of cultural heritage一 Procedure for the analytical evaluation to select cleaning methods for porous inorganic materials used in cultural heritage.
5.2 Identification of substrate and characterization of unwanted materials
The chemical, mineralogical and the micro-structural characteristics of the material constituting the object shall be known or preliminarily identified (EN 16515) as well as the extent, nature and thickness of the unwanted materials to be removed.
The layer of unwanted materials and the altered surface of substrate shall be distinguished from each other at the investigation stage, so that the required degree of cleaning can be determined (see
EN 17 138:2018, 5.2).
The preliminary investigations using non-invasive systems should be carried out on a defined trial area selected as representative of the main surface material composition and cleaning problem.
The main non-invasive systems to be considered are:
a) portable microscope for optical observations;
b) portable XRF equipment for the identification of chemical elements;
c) portable fluorescence induced by tJV radiation equipment for the identification of fluorescent compounds;
d) portable FTIR spectrometer especially in the presence of organic materials.
For laboratory investigations the procedure reported in EN 16515 (examination of specimens under stereo-microscope, petrographic examination, mineralogical analysis by X-ray diffraction XRD, examination by SEM/ESEM, chemical analysis) shall be performed.
The identification of organic components, not considered in EN 16515, shall be performed by FTIR spectroscopy and when necessary by GC-MS (gas chromatography and mass spectrometry).
5.3 Selection of suitable cleaning methods to be tested
As some cleaning methods are inappropriate where painted finishes are present, their presence or absence shall be established before any evaluation is started.
After the identification of the substrate and of the composition of unwanted materials a selection of suitable cleaning methods, according to the results obtained, is carried out on the trial area”.
For the application of this document the following cleaning method categories are considered (see
EN 17138):
a) water cleaning (restricted to the following: nebulous spray or intermittent mist spray, water spray at low pressure, steam cleaning, aqueous poultices or packs with absorbent material);
b) mechanical cleaning (restricted to the following: micro blasting, wet jet micro blasting, cryogenic cleaning);
c) chemical cleaning (application of organic solvents, application of acidic or alkaline solutions, application of chelating agents, application of surfactants, gel cleaning, application of ion exchange resins);
d) physical cleaning (laser cleaning);
e) those cleaning methods not adjustable by changing physical known parameters (such as cleaning with a lancet or a brush) are excluded by the present standard.
5.4 Localization, delimitation and numbering of the cleaning trial areas
Trial areas should be selected in order to be representative of the whole (constituting materials, surfaces and materials to be removed); if possible, trial areas should be unobtrusive. The trial areas should be the minimum size possible, taking into account the selected cleaning method, the significance of the object and the evaluation procedure, while still being representative.
The trial area(s) selection process should also take into account:
— the decay patterns, the type of substrate and the nature of unwanted material;
— the object size;
— the number of trial test required;
— the location where the impact of cleaning trials has the least detriment to the significance of the object, in case the trial should over-clean or otherwise damage an area;
— further optimization of the parameters of the selected cleaning process.
The description of trial areas selection and procedure is reported in Annex A, which is normative.BS EN 17488 pdf download.
