content_image/469802.jpg
## 5.3.3.6 Gas system 

Natural gas shall be made available by the Contractor for the heating of buildings if required in the herewith Employer’s Requirements. Gas pipelines shall meet the requirements of local standards and regulations. 

## 5.3.4 Pipe markers 

Water, wastewater and surface water pipes, manhole elements and fittings shall be marked either by carving and painting text or by thermally transferred water resistant paint. 

Pipe marks shall have the following information: 

 The name of the Municipality 

 The name of the water and sewerage administration 

 The name of the pipe factory 

 The pipe class, diameter and production date. 

## 5.3.5 Pipe materials 

## 5.3.5.1 General 

Generally all pipes, valves and pipe fittings installed shall conform to the relevant international norms and standards. The Contractor shall, if required, forward to the Engineer certificates showing that the materials have been tested and comply with the requirements of this specification and the relevant standard. 

Pipes shall be ordered in the maximum lengths available to minimize the number of joints. The Con- tractor shall be responsible for the supply of all materials in sufficient quantities and shall immediately prior to placing any order, especially for imported goods, ascertain the required quantities. 

In the following is listed the pipe materials that are found appropriate and relevant for installation in the wastewater treatment plants and pipelines to be constructed and depending on the media to be transported. 

<img src='content_image/469802.jpg'>

