How long is the QBQ certification valid and how does the exam work?

The acronym QBQ is the label of the preparation offered by Metierium: no official Quebec source names a body with that acronym, so there is no QBQ certification with a fixed validity period. Validity and renewal rules are those of the body that issues the qualification.

What the sources publish:

• Two possible certifications, depending on the nature of the work: a certificate issued under the Act respecting pressure vessels, or a certificate issued by the Canadian Welding Bureau (CWB) — Commission de la construction du Québec, Fonds de qualification de soudage
• Personal qualification falls under Emploi-Québec; company qualification falls under the RBQ and must comply with the ASME Boiler and Pressure Vessel Code, Section IX — Régie du bâtiment du Québec, Qualifier ses soudeurs
• Published test (Class A certificate, pressure vessels): a 3-hour practical examination, a nominal 2-inch steel pipe in the 6G position (inclined at 45°), checked by radiography under ASME Section IX — Government of Quebec
• CSA W47.1 certifies the company, which then qualifies its welding supervisors and engineers, submits its welding procedures for approval and qualifies its welding personnel (welders or operators)

Duration, fees and renewal therefore come from the issuing body (CWB, Emploi-Québec, RBQ), not from a single schedule.