306A Pipe Joining and Fitting Methods

Question 1

What type of solder is required for copper joints in potable water systems under the National Plumbing Code of Canada?

Accepted Answer

Lead-free solder containing no more than 0.2% lead

Answer

The National Plumbing Code of Canada requires lead-free solder to prevent lead contamination in potable water systems.

Question 2

After cutting rigid PVC pipe with a hacksaw for a solvent-cemented joint, what must be done to the pipe end before applying primer?

Accepted Answer

Deburr and chamfer the pipe end to ensure full insertion and avoid scraping cement from the socket

Answer

Deburring and chamfering removes sharp edges that would scrape cement from socket walls and ensures the pipe seats to full depth for a strong solvent bond.

Question 3

What is the standard taper for NPT (National Pipe Taper) threads used on steel pipe fittings?

Accepted Answer

1 in 16 measured on the pipe diameter (3/4 inch per foot)

Answer

NPT threads have a standardized taper of 1 in 16 on the diameter, creating the wedging interference fit that seals the joint.

Question 4

When making a crimp-ring connection on PEX tubing, which tool verifies that the crimp ring has been correctly compressed?

Accepted Answer

A go/no-go gauge that measures the outer diameter of the crimped ring

Answer

A go/no-go gauge checks that the compressed crimp ring diameter falls within the specified range, confirming the connection is neither under- nor over-crimped.

Question 5

Which type of flux must NOT be used when soldering copper pipe in a potable water system?

Accepted Answer

Acid (active) flux containing zinc chloride

Answer

Acid flux contains zinc chloride which is corrosive and toxic; residue left inside a pipe would contaminate drinking water and accelerate internal corrosion.

Red Seal Plumber 306A Practice Test

Red Seal Plumber 306A Practice Test

306A Pipe Joining and Fitting Methods