Pre-action: ask which interlock, not just which name.

The concept

Concept: Separate detection and a release arrangement are part of the system. The conditions for admitting water depend on the interlock design. This illustration shows a detection-and-open-sprinkler scenario. Use the system explorer to compare these concepts. It does not model your building, response times, coverage or hydraulic performance.

Single-interlock, double-interlock and non-interlock arrangements differ. The Viking reference explains those categories for its documented systems; that older manual is not the current service instruction for your equipment. Ask the qualified provider to establish the installed arrangement and obtain current model-specific documents.

Document the system identity

• Available design and acceptance records.
• Installed valve and release-equipment identification.
• The documented interlock arrangement.
• Detection, alarm and supervisory interfaces.
• Who maintains each part and who coordinates a joint visit.

If a building record says only “pre-action,” mark the missing detail as a question. Do not infer double-interlock protection from a room’s contents or from a generic brochure.

Make interface ownership visible

A sprinkler contractor and an alarm or detection provider may need to coordinate. Ask who owns the combined scope and which records establish that the interfaces were checked. Two unrelated invoices do not necessarily describe the whole arrangement.

For changes to the protected space, bring the design and connected-equipment teams into the review. New partitions, equipment or intended use can create questions that a routine maintenance visit did not assess.

Discuss the protected contents responsibly

Explain why the area matters operationally and any access restrictions. Do not promise that a particular system eliminates water damage or accidental discharge. Have the project team assess the actual hazard, design and operating requirements rather than selecting a configuration from a preference for keeping things dry.

Keep security-sensitive floor plans, server details and access codes out of an initial website enquiry. Arrange a suitable document channel with the provider.

Ask for the right service plan

Request the scope and programme covering both sprinkler and connected release equipment. Confirm what report is supplied, how findings are escalated and what follows a repair or modification. This website does not provide release, reset, alarm-bypass or restoration procedures.

References and scope

1. Preaction system technical manual — Viking Corporation. February 2010 manufacturer manual, used for the distinction between interlock concepts only. Obtain current, exact-model documents for a real system.
2. Types of fire sprinkler systems — National Fire Sprinkler Association. Conceptual wet, dry, pre-action and deluge overview. US association guidance does not settle Canadian code requirements.

Source links checked 2026-09-30. This is not a professional review, certification or building-specific determination.