Construction Noise and Vibration Studies and Monitoring in Quebec

Contractors on public infrastructure projects in Quebec are subject to construction noise and vibration conditions written into the contract by the project owner. Transit authorities, Hydro-Québec, the transport ministry, municipalities, and institutional owners require the contractor to demonstrate, before noisy work begins, that its methods, equipment, and schedule will keep sound and vibration levels at neighbouring buildings within the contract limits. A construction noise study provides that demonstration, in the form of a noise control program the owner approves before mobilization.

The study is the first stage of the mandate. Where the predicted levels approach or exceed a limit for part of the work, the program specifies monitoring during those activities, and the owner or the municipality makes monitoring a condition of proceeding. Monitoring then provides a daily record of the sound and vibration levels at each neighbouring building, and represents most of the acoustical work on the project.

Construction Noise and Vibration Requirements in Quebec Contracts

The noise requirement originates in the provincial guideline for construction site noise, the Lignes directrices relativement aux niveaux sonores provenant d’un chantier de construction industriel, which project owners carry into their contract clauses, sometimes with stricter values of their own. The guideline sets a sound level limit at residences, hospitals, schools, and similar locations for each period of the day, and allows evening exceedances only with a documented justification. At night, exceedances are permitted only in an emergency.

Municipal noise bylaws often specify the hours during which construction work is permitted, and vary by municipality.

Vibration limits are established for each project, from the construction of the neighbouring buildings and the recognized criteria for each type of structure, with stricter values for heritage buildings and for premises housing sensitive equipment.

Owner clauses typically require a general noise control program before work starts, a detailed program before each construction activity, a monitoring plan, and, where buildings are at risk, a condition survey before and after the work.

Construction Noise and Vibration Study and Monitoring Program

The study typically includes the following work:

• Contract and site information — Sonvera requests the owner’s noise and vibration clauses, the construction schedule and method statement, and the equipment list for each phase
• Receptor mapping and baseline measurements — the residences, institutions, and buildings at risk around the site are identified, and existing sound and vibration levels are measured at representative locations over the periods the contract specifies
• Phase-by-phase prediction — sound levels at each receptor are predicted for each construction phase from the equipment emission levels, positions, and hours of operation, and vibration levels from the equipment and distances involved, and both are compared with the applicable limits
• Noise control design — Sonvera works with the contractor to identify the most appropriate measures, from scheduling and equipment selection to temporary barriers and enclosures, selected for what can realistically be implemented within the schedule and the site constraints, and predicts the resulting levels
• Noise control program — the study is assembled in the owner’s required format, with the justification for any activity requiring an exemption

Where monitoring is required, it typically includes:

• Monitoring plan — the buildings where sound and vibration are monitored, the limit applicable to each one, the instrument locations, the alert thresholds, and the reporting
• Condition survey — the condition of each building within the zone of influence is documented in writing and in photographs, including every existing crack and defect, before the work begins and again after it ends
• Continuous monitoring — unattended stations record sound and vibration levels throughout the work, transmit the data continuously, and raise an alert when a threshold is reached, so that the activity can be adjusted before a limit is exceeded; stations are installed for the duration of the activities concerned and relocated as the work advances
• Reporting — measured levels are reported at the cadence the contract requires, each vibration peak with its frequency and its source activity, with the exceedances and the corrective measures documented

The result is a signed noise control program built to satisfy the owner’s requirements, and a continuous record of the sound and vibration levels measured at each neighbouring building.