Sprinkler System Certifiers – Q3 Update
Our Sprinkler System Certifiers updates provide recent industry developments and solutions to common industry challenges faced firsthand – to ensure you are better informed and better advised to make better decisions.
Design Parameter Reviews
A requirement of the Sprinkler Standard is that before work starts on site, a design parameter submission is submitted to the Sprinkler System Certifier. The purpose of this procedure is to ensure that significant issues are identified that could impede the ability to certify an installation. Obviously, the quality of information provided will dictate the quality of a review.
The issue: When we generate review letters, it is important that any issues we have identified are addressed. If the reason we have requested further information is unclear, please seek clarification. On occasion, we have asked a pertinent question, and have received a reply with the completion documentation, which has made certification problematic.
We have seen a recent trend where design parameter submissions have been submitted very late in the construction phase – in some cases, after the project has been completed. In one project, the design was fundamentally wrong, and the system had to be significantly reworked.
Our Q1 update included the need to ensure that the building owner and tenants are aware of the design capacity of sprinkler systems. Please remember that the designer needs to understand what will be installed in the building, including packaging materials, idle pallets, and special risks such as ignitable liquids and aerosols.
Key takeaway: The design parameter review process is not a box ticking exercise, but a process to protect all stakeholders, including the building owner and fire protection contractor, to ensure that a safe and reliable sprinkler system can be certified at the end of the project.
Freezer Gaskets
The issue: The pipe work of a dry or preaction system for a freezer must be installed in such a manner that there is no trapped water. If there are water traps this can result in two separate problems. Firstly, any ice in the pipe will restrict the free flow of water and in the worst case, completely block the flow of water to the sprinkler. Secondly, as water expands when it freezes the formation of ice exerts internal pressure on the pipe and fitting, often leading to catastrophe failure of the pipe or fitting.
To ensure there is no risk of ice formation within the gasket or casting of a roll groove coupling, the manufacturers have specific designs for the gasket that exclude water from entering the seal.
Key takeaway: Make sure when ordering and installing roll groove couplings for freezers and low temperature chillers the gasket is rated by the manufacturer for freezer applications.
Single Knock, Double Knock, Single Interlock and Double Interlock
We often see confusion by parties with the different terminology for single knock, double knock, single interlock, and double interlock. Single interlocked preaction systems can be used in most places about a building; one notable exception being inrack of a dry system. The Standard reserves double interlock for sub 4 degree temperature controlled spaces.
Single or double knock. This refers to how many separate events must occur on the detection system before it is seen as a potential event. For example, a double knock system may have both an aspirating smoke detection and the detection sprinkler line; both need to activate before the preaction control panel registers that the detection has activated. While double knock on a preaction system is very rare it is very common on gas flood installations.
Single or double interlocked. This refers to whether the alarm valve opens if the detection only activates, which is single interlock; or if the alarm valve opens only when both the detection and the protection activates, which is double interlocked.
Whether the system is single interlocked or double interlocked if only protection system loses pressure the alarm valve does not open. In this case the system will only register a defect condition.
Sprinkler Wrenches
A consultant designer brought the following photograph to our attention. It shows a sprinkler fitter using an adjustable wrench to install a storage sprinkler.
The issue: While this used to be an acceptable practice, sprinkle manufacturers now state that their wrenches must be used to install sprinklers. This is because of sprinklers spontaneously releasing, when the adjustable spanners have slipped.
It is also important to ensure that sprinklers are not over-tightened. Sprinkler manufacturers will identify if sprinklers have failed due to over-tightening, or from mechanical damage caused by the use of wrong wrenches. In one investigation, where high valued goods were damaged by a release, the investigation identified that the contractor had not purchased the correct spanners.
On a positive note, when this issue was brought to the attention of the sprinkler contractor, the heads were replaced.
Key takeaway: Use of correct wrenches will reduce the probability of accidental damage during installation, which will not only help prtect the facility from water damage, but will protect the sprinkler contractor from the costs of defending insurance claims.
Flow Switch Testing
Recently, the certification of a project was delayed because confusion arose around who was to test the flow switches. In this case, the flow switch provided a critical function as the building had managed evacuation; hence properly testing the flow switch is of the upmost importance.
The issue: Is it the fire alarms or fire sprinkler trades responsibility, and in turn their respective inspector?
It is the SSC’s view that either the fire alarms or the fire sprinkler inspector can complete this test; but they must do it properly by operating the flow switch test valve and then allowing the fire panel to operate the respective evacuation zone.
It is quite common for initial testing of flow switches to be done by removing the cover and either shorting the terminals or pushing the paddle across. While this confirms the correct flow switches have been mapped to the correct zone, it is not a proper test. Two cases demonstrate why such testing is flawed. In one case, after a 20 zone hospital level care home had been presented to the project fire engineer for confirmation, who signed off the evacuation as correct, the sprinkler inspector visited and tested the flow switches. The sprinkler inspector found one bank of five flow switches all failed to operate; when the installing contractor looked harder, they realised the flow switches had been installed backwards. In a second case, after the installing contractor had completed their own commissioning, the sprinkler inspector when testing found that one flow switch failed to operate. When the installing contractor investigated the problem, it turned out that there was a casting burr on the flow switch cover that prevented the flow switch mechanism moving freely.
Key takeaway: End to end testing must be conducted of flow switches by operating the flow switch test valve and allowing the evacuation to start.
In-Rack Sprinkler Locations
We had feedback from a consultant that some installers seem to be unaware of the new requirements in NZS4541:2020 regarding the required location for in-rack sprinklers. Clause 9.4.2.4 (c) requires that in-rack sprinklers are not located where they are baffled by uprights, but no more than 75mm away from the lateral flue space they are protecting. This is illustrated below.
(Image courtesy of Protech Design Limited.)
Key takeaway: This is a reminder to designers and installation fitters that the placement rules for in-rack sprinklers have changed.