DIBt approval guidelines for the health-related evaluation of indoor construction

Products)

Based on the AgBB's VOC/SVOC evaluation scheme, the Deutsches Institut für Bautechnik (German Institute for Building Technology – DIBt) has further developed this procedure to achieve an evaluation basis for issuing allgemeine bauaufsichtliche Zulassungen ('national technical approvals') for indoor construction products [96]. The DIBt Approval Guidelines for indoor construction products are divided into two parts. Part I "General evaluation concept"

specifies the procedure for the health-related evaluation of indoor construction products, which is to be applied to all construction products under examination. In Part II, "Evaluation concept for special construction products", the general concept is fine tuned for groups of special construction products and put into concrete terms regarding the testing procedures to be used. The product-specific Part II is so far available for the construction product group

"Floorings and adhesives". For further products relevant to indoor spaces, corresponding product-specific requirements are being successively developed.

Part I "General evaluation concept" [96]

The evaluation concept of the DIBt approval guidelines is divided into two stages. The first stage deals with the substances used in the construction product. Information on this is provided by the chemical composition of the product, which the applicant discloses to the DIBt. The substances are assessed using the following criteria for exclusion:

• Legal prohibitions and restrictions for specific substances (e.g.

Chemikalienverbotsverordnung ('Prohibition of Chemicals Ordinance')

• Prohibitions and restrictions stipulated by the DIBt for potentially dangerous substances in construction products.

• Substances which are labelled "Very toxic" (T+) or "Toxic" (T) in accordance with EU Directive 67/548/EEC [3] should be avoided. Should it not be possible to avoid using a substance for technical reasons, a special evaluation shall be carried out.

• Carcinogenic (T, R45, T, R49) and mutagenic (T, R46) substances may not be actively used.

• If waste (for reuse) is utilized when manufacturing construction products, the pure and undiluted waste shall be examined and evaluated separately. If necessary, suitable tests shall be carried out.

• When using waste wood, the provisions of the Altholzverordnung ('Waste Wood Ordinance') [97] shall be complied with.

• Mineral wastes used must meet the requirements of LAGA-Mitteilung 20 "Anforderungen an die stoffliche Verwertung von mineralischen Abfällen" (LAGA Rules "Requirements for re-use/utilization of mineral residues/wastes") [27].

Even if only one exclusion criterion applies, the construction product does not conform with the DIBt Approval Guidelines and an approval cannot be issued. However, a construction product already fulfills the requirements after the first stage if, due to the chemical composition, it can be assumed with sufficient certainty that the construction product does not represent a hazard to the indoor air or if construction products with a similar composition have already been tested after the second stage and complied with the requirements of the DIBt Approval Guidelines.

The second stage of the evaluation concept considers the substances that can be released.

This stage corresponds to the AgBB's VOC/SVOC evaluation scheme (c.f. Section 6.1.1).

The following flow diagram illustrates the procedure of the DIBt Approval Guidelines:

Health-related evaluation of VOC and SVOC emissions from construction products according to the AgBB's VOC/SVOC evaluation scheme

(see Section 6.1.1, Fig. 4)

Fig. 5: Flow diagram showing the health-related evaluation of construction products according to the DIBt approval guidelines for the health-related evaluation of indoor construction products [96]

Part II "Evaluation concept for special construction products": Floorings and adhesives [96]

Part II "Floorings and Adhesives" applies to the approval of flame resistant floorings that are used glued or unglued in lounges.

The substances used in the respective construction products are determined and evaluated in line with stage 1 of the general evaluation concept in Part I. There are no particular requirements that only concern floorings and adhesives.

When determining and evaluating the emission of volatile and semi-volatile organic compounds according to stage 2, formaldehyde is also determined and evaluated in addition to VOC and SVOC provided that free formaldehyde or formaldehyde resin is actively used for the manufacture of the product. The emission of formaldehyde can also be determined according to DIN EN 13419-1 or –2 (Draft) [91, 92]; the analysis is conducted according to DIN ISO 16000-3 [98]. If the formaldehyde testing is carried out with wood-based panels, the emission testing shall be carried out in accordance with the provisions of the German Chemikalienverbotsverordnung ('Prohibition of Chemicals Ordinance') [99].

Requirement fulfilled Construction product

Exclusion criteria fulfilled?

Knowledge on the health compatibility -or comparison with similar positively

evaluated products?

Stage 1

Stage 2

Rejection

Yes

Yes No

No

Determination of the constituents (formulation /analysis)

The sampling, packaging and storage of the samples shall be conducted according to DIN EN 13419-3 (Draft) [93]. With all flooring types, it is essential that the products tested are as fresh off the production line as possible.

The fabrication and preparation of the test sample shall also be conducted according to DIN EN 13419-3 (Draft) [93]. However, specifications for that are given where the start of the emission test t₀ is defined. Here the emission testing for textile, resilient and rigid floorings that have been sealed in the factory begins immediately on completion of the test specimen.

Floor covering systems, adhesives and rigid floorings that are sealed on site shall be applied in liquid form on a suitable substrate and preconditioned for 72 hours in the test chamber. It is only then that the actual emission measurement according to DIN EN 13419-1 or -2 (Draft) begins in another emission chamber [91, 92].

The emission testing shall be conducted with an area-specific airflow rate of q = 1.25. The first measurement shall be conducted after 72 hours, the second measurement after 28 days.

The analytical determination of VOC and SVOC is based on ISO 16000-6 [94]. In deviation from the standard, which defines VVOC, VOC and SVOC by means of their boiling points, as does the WHO, the DIBt Approval Guidelines define the three substance groups analogous to the AgBB's VOC/SVOC evaluation scheme on the basis of the carbon structure and the retention times. Furthermore, the DIBt Approval Guidelines provide specific information on identification and quantification.

The evaluation of the VOC and SVOC emissions corresponds to the general evaluation concept procedure from Part I.