4) What is the remedial measure to stop the dripping of water from house hold tap even after firmly closed?

5) How pipes are classified?

6) Which standard pipe fitting is used to close a pipe line having internal thread?

7) Which type of wrench is used for more than 50 mm diameter pipe to tight with heavy gripping?

8) What is the remedy if the spindle rotates continuously so that the gate valve is not closed?