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Protocol for internal inspections
In the Netherlands, a request has been made by the business community to inspect the internal condition of the pipe network of sprinkler systems. In order to prevent inspection bodies from all dealing with this in a different way, it has been agreed to draw up an inspection protocol. By making use of this protocol, Sven Sterkendries of Normec explains, all end users are assured that inspection bodies can assess the internal condition of the pipeline network in a harmonised manner.
The purpose of this inspection protocol is to enable an assessment of the performance of the installation in relation to the internal condition of the pipe network and the functionality of the sprinklers. By working in a structured manner according to a predetermined plan, the inspection can be carried out efficiently and effectively. An internal inspection of a sprinkler installation consists of an inspection of the pipework and an inspection of the sprinklers.
Preparation
Before the inspection can be carried out, all documents (drawings) must be available. A cherry-picker may need to be reserved and certain work areas may need to be cordoned off for safety.
It is important that the planning is properly described prior to the inspection. Make sure the division of labour is clear to all parties involved so that all work can be done efficiently and according to plan.
Broadly speaking, the inspection consists of two parts: the inspection of the pipe network and the inspection of the sprinklers. The scope and location of the inspections must be clearly determined in advance and recorded on the drawing. During the inspections, as much visual material (photos and videos) as possible must be collected.
An inspection report must be drawn up and must include the general details of the building, a description of how the inspections were carried out and a conclusion of the inspection. The inspection report must undergo a peer review before it can be sent to the client.
It is a perquisite that the inspection plan is sent to all parties before the start of work so that everyone is informed and adjustments can be made if necessary.
Conducting the inspection
The pipework must be flushed before the start of the inspection and to do this, the section concerned must be temporarily decommissioned. The user must carefully observe the decommissioning regulations for this. Consider, for example, informing the fire brigade and insurance companies, applying alternative fire safety measures, etc.
Before conducting the internal inspection of the pipework, the pipe network shall be flushed and all main and manifold lines must be flushed through the flushing valves. When flushing, a filter with a maximum mesh size of 1 mm must be fitted. Flushing continues until there is no more contamination in the filter.
During the inspection of the pipework, the subjects below must be recorded in the inspection plan.
Pipework inspection
Scope of the inspection At least 20 m sprinkler pipes and 7 m distribution or main pipes per 5 alarm valves. Alternatively, a different size may be determined in consultation with the inspection body
Location of the inspection
Assessment method
Assessment criteria The assessment positions should be evenly distributed among the sprinkler sections. Risks such as sagging in the pipework, environmental influences and leaks must be considered
The pipework can be assessed by endoscopic examination or at anywhere the system is opened (for example, where sprinklers are replaced or when servicing an alarm valve)
The free internal cross-sectional area of the pipework must be at least 90% of the nominal cross-sectional area
Table 1 – Pipework inspection
The pipe sections to be inspected must be indicated on a drawing and the observations must be recorded in photos and / or videos.
When inspecting the sprinklers, the subjects below must be recorded in the inspection plan.
The sprinklers to be inspected must be indicated on a drawing and the observations must be recorded in photographs and / or videos. The sprinklers removed must be stored in such a way that they retain the properties they had when installed. Sprinkler drying or contamination can affect the results of the assessment.
Sprinkler inspection
Accreditation The sprinklers must be assessed by a laboratory that is accredited for testing sprinklers in accordance with NEN-EN 12259 or the inspection protocol.
Scope of the inspection The number of sprinklers to be assessed depends on the number of sprinklers installed per type.
Selection of sprinklers for assessment Sprinkler selection should be evenly distributed throughout the installation.
Assessment criteria The activation temperature, the K-factor and the minimum pressure at which the sprinkler opens must be assessed.
Table 2 – Sprinkler inspection
The inspector
Requirements are also imposed on those who conduct the inspection. The inspector must be qualified for sprinkler systems and competent to: estimate the risks of corrosion and blockage in an installation select pipe sections where corrosion or blockages can occur select sprinklers where poor results are expected (changes in ambient temperature, chemical influences, etc) interpret camera images of the internal condition of the pipes assess the effect of the corrosion or blockage found on the efficiency of the installation
Frequency of internal inspections
The frequency of the internal inspection depends on the standard that is applied. On the basis of NEN-EN 12845, as described in Appendix K, the pipes and sprinklers must be inspected after 25 years. Annex K is described in the Dutch standard (NEN-EN 12845) as “normative” and must therefore be applied. In the European standard (EN 12845), Annex K is “informative”.
When other standards are used (such as NFPA 25 or FM 2-81), this is handled in a different way and with a different frequency.
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