AGF Manufacturing explores how field experience influences system design to ensure that components remain accessible and compliant for technicians
Fire sprinkler systems are typically judged at the moment of acceptance.
If the system passes its hydrostatic test, flows water as expected and meets the design criteria of NFPA 13, it is often considered successful.
But experienced professionals understand that commissioning is only the beginning.
The true measure of a fire sprinkler system is whether it remains reliable, serviceable and compliant years later as the building, occupancy and environment change.
Maintainability is rarely the primary focus during system design, yet it strongly influences long-term performance.
Systems designed with inspection, testing and maintenance (ITM) in mind tend to experience fewer impairments, lower lifecycle costs and more consistent compliance with NFPA 25.
Neglected systems can become difficult, time-consuming and risky to maintain.
This article explores how field experience highlights the importance of designing fire sprinkler systems for maintainability and how understanding the roles of NFPA 13 and NFPA 25 can support long-term reliability.
Understanding the different roles of NFPA 13 and NFPA 25
NFPA 13 and NFPA 25 serve different purposes.
NFPA 13 is an installation standard focused on the design and installation of fire sprinkler systems so they perform as intended at acceptance.
It addresses system layout, hydraulic criteria, component selection and installation practices.
NFPA 25 covers what happens after installation.
Its purpose is to provide minimum requirements for ongoing inspection, testing and maintenance of water-based fire protection systems.
It assumes that the system was installed correctly in accordance with NFPA 13 and focuses on keeping it operational over time.
As stated in NFPA 25 Chapter 1, the standard establishes requirements for periodic ITM and actions when changes in occupancy, use, process, materials, hazard or water supply could affect performance.
These ongoing responsibilities are not addressed in NFPA 13, yet they strongly influence system reliability.
A system can be fully compliant with NFPA 13 at installation and still be difficult to inspect, test and maintain in accordance with NFPA 25 if long-term access and service needs are not considered during design.
Code compliance vs long-term serviceability
Field experience shows that code compliance and serviceability are not always aligned.
A system may meet installation requirements yet place valves above hard ceilings, locate drains in impractical discharge areas or rely on test procedures that are difficult once the building is occupied.
These conditions complicate NFPA 25 compliance.
When systems are difficult to access or understand, inspection and testing become harder to execute consistently, increasing the likelihood of missed inspections, incomplete testing or deferred maintenance.
Designing with long-term serviceability in mind helps close this gap between installation compliance and operational reliability.
Accessibility and valve placement
Accessibility illustrates how NFPA 13 and NFPA 25 intersect while serving different goals.
NFPA 13 requires certain components, particularly control valves, to be accessible and visible from the floor so they can be located and operated quickly during emergencies.
NFPA 25 also requires control valves to be accessible, but its focus is inspection, testing and maintenance.
Sectional control valves are expected to be accessible without ladders or special tools.
Other valves may be accessed less frequently but must still be reachable for maintenance.
Clear identification of valve function and appropriate access reduce confusion and improve compliance with both standards.
Designing for drainage and low points
Water migrates to the lowest point in a sprinkler system, where trapped water, debris and corrosion byproducts accumulate.
NFPA 25 requires auxiliary drains where trapped water is likely.
Low points may exist without proper drains, or drains may be installed where they are difficult to locate or operate.
Designing for maintainability means identifying and labelling low points and providing documentation on quantity and location for each dry or preaction system, reducing the risk of missed maintenance and freeze damage.
System stability over time
Air management is another area where installation intent and long-term performance can diverge.
While NFPA 13 requires air vents to remove trapped air in wet systems, air-related issues often emerge years later due to system modifications or ageing infrastructure.
From an ITM standpoint, trapped air complicates testing, contributes to corrosion and can produce inconsistent pressure behaviour.
Main drain tests often reveal these issues through abnormal readings or slow pressure recovery.
Designers who consider how air will be managed throughout the system’s lifecycle can specify air vents at multiple high points and corrosion monitoring at susceptible locations, creating systems that are more predictable and easier to maintain.
Simplifying testing
Systems that are difficult to test increase the likelihood that inspection and testing requirements become burdensome or inconsistently applied.
Clear identification of test valves, logical layouts and intuitive testing configurations help technicians perform required tests accurately and repeatedly.
When procedures are straightforward, they are more likely to be completed correctly and documented properly.
Designing for the entire lifecycle
Fire sprinkler systems are long-term assets expected to perform for decades.
NFPA 13 ensures systems are installed correctly, while NFPA 25 ensures they remain operational as conditions change.
When systems are designed with accessibility, serviceability and long-term ITM in mind, compliance becomes more consistent and reliability improves.
Maintainability should form part of the design review so ITM needs are addressed from the start, supporting safer buildings and greater confidence that systems will perform when required.