Research Article

Enhancing Interpretability of Data-Driven Fault Detection and Diagnosis Methodology with Maintainability Rules in Smart Building Management

Table 5

HVAC System - Air Handling Unit (AHU).

ProblemDesignConstructionMaintenance

Air distribution system efficiency

Broken fan belt

Blue/grey formicary corrosion on Al-cu cooling coil
The design of an AHU system must take into consideration energy efficiency and maintainability when selecting the system and its components. Design AHU in accordance with ANSI/ASHRAE/IES standard
90.1/SS 553 or equivalent.
Fan power limitation requirements in mechanical ventilation systems to comply with SS 553, AS 1668.2 or equivalent.
Specify minimum performance for air- conditioning equipment (including test procedure) in accordance with SS 530, ANSI/ASHRAE/IES standard 90.1 or equivalent. Propose a biological film application on cooling coil.
It is presupposed that the installation (and subsequent operation) of the AHU is in compliance with statutory and regulatory requirements.
For the vibration control of fan systems, refer to CP 99 for the installation/commissioning in accordance with ISO 9996 or equivalent.
Install/integrate AHU system components (e.g. VFD, control dampers/actuators) off-site to ensure quality installation.
Clean dirt from impeller, fan scroll and blower blade, washable filters, filter frames and AHU frame slot. Clean cooling coil face with water. Flush with chemical cleaner, but avoid over dosage. Chemical wash should be carried out followed by thorough cleaning with water. Check for any dents on the coil fins. Comb/replace as needed. Clean off any hardened and dirty grease or grime from fan and motor shaft and lubricate properly.
Do not use AHU rooms for storage and avoid housing installations that are not associated with the air- conditioning system, in accordance with SS 553, AS
1668.2 or equivalent.
Noisy operation and excessive vibration

Noisy fan motor

Good practice: Install a connection box on AHU for vibration monitoring
Careful design is necessary to reduce vibration disturbances caused by impact force. Conform to noise control and elimination guidelines. Use principles of vibration control in determining noise control measures in accordance with SS CP 99, AHRI 260, ISO 9996 or equivalent.Use acoustic silencers, shock isolators, machine enclosures and partition walls to reduce noise disturbances. Use vibration isolators/mounting of equipment to minimise transmission of vibration from machine to load-bearing structure of the building in accordance with ANSI/AHRI Standard 260, CP 99, ISO 9996 or equivalent.
Recommend installing vibration monitoring equipment for AHU to assist in predictive maintenance.
Inspection should be carried out to determine noise levels (ANSI/AHRI standard 260). Inspect chiller plant with maintenance experts if abnormal sound occurs.
Isolation/mounting systems should be provided to reduce mechanical vibration and shock in accordance with ISO 2017-1 or equivalent. Vibration from bearings, and sliding and rolling friction could be reduced by maintaining minimum clearances and proper lubrication in accordance with CP 99, ANSI/AHRI Standard
260 or equivalent.
Regular monitoring of AHU fan vibration should be carried out and compare with the vibration readings specified in ISO 10816-3 or equivalent.