TIMBER PILING (CONT’D) (m) Cutting off of Piles

Excavate and cut off the pile to the required level shown on the pile layout Drawings or otherwise directed by the SO Rep. Checking and recording of cut-off level shall be followed up immediately.

In the cutting of piles, ensure that a surveyor is stationed at the Site for such work.

Do not reuse any pile which has been cut off as wastage unless the waste pile length exceeds 2.5m and the cut-off head has been treated.

2.30 PAINTING

(a) Material

All paints, primers and other materials shall comply with SS5, SS6, SS7, SS34, SS37, SS38, SS150, SS206 and SS345 or other relevant specifications of PSB.

(i) Enamel Gloss Paint

Paint for timber and metal work shall have a synthetic enamel gloss finish with an alkyd-resin base.

Where an undercoat is specified, obtain the paint from the same manufacturer whose gloss paint is approved for the particular work. A different brand shall not be used unless the SO Rep has given his consent.

If more than one under-coat is specified, the undercoats shall be of different colour from each other to enable the number of coats applied to be checked. Before the following coat is applied, allow each coat at least 24 hours to dry. Carry out painting with proper paint brushes. Any other method of painting shall not be allowed unless approved by the SO Rep.

(ii) Primers

Primer for aluminium, zinc or galvanised iron shall be an approved Etching Primer with a Polyvinyl resin base and then cover with another coat of approved lead and chromate free primer with a pure linseed oil base. Thoroughly mix etching primer with the Activator before use in the ratio of 3 parts Base to 1 part Activator. Being a dual pack material, the mixture shall have a pot life of 12 hours.

Carry out the painting of etching primer coat under shed or in the factory.

The dried etching primer coat shall not come in contact with water and apply a coat of Red lead primer over it within two days from the date of applying the etching primer.

(iii) Emulsion Paint

All emulsion paints shall be of an approved brand with an acrylic base. Apply with a proper paint brush and not a locally made colour wash brush. If more than one coat is specified the previous coat shall be properly dried before the following coat is applied.

(iv) Carriageway Marking Paints

All paints used for carriageway marking shall be quick-drying, chlorinated rubber based and shall comply in all respects with the requirements specified in the Singapore Standard 221:1979 (UDC 667.633:625.746) for Road Marking painting. The Contractor may

2.30 PAINTING (CONT’D) (a) Material (Cont’d)

(iv) Carriageway Marking Paints (Cont’d)

The SO Rep may direct the Contractor to change the supplier or manufacturer of the paints used in this Contract if he is satisfied that the paints used in this Contract do not comply with the Specifications and the corresponding Statement of Characteristics. Comply further with the instructions of the SO Rep all at the Contractor's own cost and expense.

The SO Rep may require samples of reasonable quantity of any paint used in the Works for testing by an SAC accredited laboratory. The Contractor shall be advised of the results of the testing by the SO Rep. If the paint tested fails to meet the approved requirements on the corresponding Statement of Characteristics, then all works represented by the paint sample or the entire road or roads painted on the same day where such paint was taken for testing shall be rejected.

Deliver all paints for carriageway marking to the Site ready for use. When the container for the paint is opened, the paint shall show no signs of livering or instability and be free from skin, dry sediment, and caking and shall mix readily with a paddle to a smooth homogeneous state.

The paint shall meet the quantitative requirements specified in the following table:

Requirement

Tests conducted by SAC Accredited Laboratory

The properties and characteristics for all road line paints used in this Contract shall if required, be tested in accordance with the methods of testing specified in and requirements inferred from the respective standard adopted by PSB.

Item Test Method of Test

2.30 PAINTING (CONT'D)

(b) Certificate

Submit a certified 'STATEMENT OF CHARACTERISTICS FOR CARRIAGEWAY MARKING PAINTS' on the prescribed Form as produced in Appendix A2. This statement shall be completed by the paint manufacturer whose paint the Contractor proposes to use in the Works. This statement shall be used to make periodic assessment of the Contractor's paints as sampled from time to time and is for the strict confidential use of the SO Rep and the information in the Statement would not be revealed by the SO Rep but shall serve and assist in identifying and testing the paint samples taken during the execution of the Works.

(c) Equipment

Mechanisation in all aspects of painting of road line and carriageway markings is compulsory under the Contract. It shall be a prerequisite for the Contractor to own and make available the following equipments for use under the Contract :

(i) Carriageway Marking Machines

The apparatus shall be self propelled and constructed so as to apply or spray paint under pressure in continuous uniformity to dimensions of the markings. It shall be equipped with the devices for agitation of the paint while in operation. All parts of the apparatus which come into contact with the paint shall be so constructed as to be easily cleaned and maintained.

The apparatus shall be capable of adjustment to provide a uniform spray wet film thickness of between 200 to 500 microns and in this respect shall be automatically self drive and be capable of travelling at uniform speed. It shall be mobile and manoeuvrable to the extent that straight lines can be followed and regular curves can be prescribed in a true arc. The apparatus shall have the capacity of selection of either automatic or manual skip marking operations preferably to four preset programmes. The apparatus shall also be capable of marking line widths varying from 100mm to 600mm with extended facilities of applying paint to symbolic signs and messages using templates.

The marking apparatus shall also be equipped with devices capable of applying glass beads balloting in such a manner that the balloting are dispersed almost instantly upon the freshly painted surface at a rate of 0.72 kg per litre of paint or at the recommended rate of the paint manufacturer. The balloting depositor shall be synchronised with the cut off of the paint application control. The balloting shall be applied with sufficient velocity to ensure retention in the surface of the paint.

(ii) Roadline Erasing Machine

The apparatus shall be mechanically propelled and be able to erase road lines uniformly in the cold state.

(iii) Flow Cups and Wet Films Gauges

All painting machines shall be provided with approved flow cups (ISO flow cups or equivalent) for measuring the consistency of viscosity of the paint used and wet film gauges (Ericksen type 333 or equivalent) with a measuring range of 0 to 600 microns having an accuracy of 25 microns for the determination of the wet film thickness of paint laid. Also supply six aluminium plates 200mm x 200mm of 15 gauge for the purpose of the testing of the thickness of the road line paint.

(d) Mode of Operation

2.30 PAINTING (CONT'D)