Architectural Science Review, 2014 Vol. 57, No. 3, 188–195, http://dx.doi.org/10.1080/00038628.2014.888515 Assessment of defects in HVAC systems caused by lack of maintenance feedback to the design team Mohammad A. Hassanain ∗ , Abdul-Mohsen Al-Hammad and Fady Fatayer Architectural Engineering Department, King Fahd University of Petroleum and Minerals, KFUPM, Box 541, Dhahran 31261, Saudi Arabia (Received 27 April 2013; final version received 25 January 2014 ) Research has shown that a major part of the heating, ventilation and air-conditioning (HVAC) systems’ operation and maintenance challenges is attributed to the extent of the decisions made during the design stage of projects. Transfer of knowledge from the maintenance team to the design team provides a potential for avoiding the repetition of costly design defects that maintenance teams usually encounter during the functional life of the project. This research has two objectives. The first is to identify and assess the importance of HVAC design defects caused by the lack of maintenance feedback to the design team. These defects have been identified from the literature and interviews with operation and maintenance experts. The study emphasized the importance of all the identified defects based on the judgment of the maintenance experts in 13 public universities in Saudi Arabia. The second objective is to present three sets of validated maintainability guidelines developed to reduce the occurrence of the identified defects in HVAC systems. These guidelines could be considered at three design completion phases (i.e. 30%, 60%, and 90%). This research provides a useful focus to design engineers aiming to design maintainable facilities and maintenance administrators striving to provide high-quality services to facility users. Keywords: HVAC defects; maintenance feedback; guidelines 1. Introduction As contemporary facilities are designed to meet high stan- dards, the effects of the decisions made during the design stage have far-reaching implications on the future main- tainability of these facilities (Chew, Tan, and Kang 2004). The concept of maintainability should be considered dur- ing the design and construction phases to reduce the cost and difficulty of maintenance works (Chew et al. 2008). Maintainability is defined as “the ability to achieve the optimum performance throughout the lifespan of a facil- ity within the minimum life cycle cost” (Chew 2010). Faulty design leads to the occurrence of building defects which require costly maintenance. Design professionals should be keen to consider the effects of their decisions on the extent as well as the cost of maintenance during the life cycle of the building (Arditi and Nawakorawit 1999a, 1999b). The heating, ventilation and air-conditioning (HVAC) systems are one of the most intricate systems in building projects. These systems should be designed to satisfy the thermal comfort requirements of the building occupants. Moreover, designers should ensure that the components of the HVAC systems are accessible for conducting the required diagnosis and maintenance activities (Merritt and Ambrose 1990). The design decisions pertaining to the ∗ Corresponding author. Email: mohhas@kfupm.edu.sa provision and the layout of several components in the HVAC systems have a considerable impact on the ease of conducting maintenance during the functional life of buildings (Estill et al. 2002). The functional life of build- ings is defined as “the period from construction to the time when the building ceases to function for the same purpose as that for which it was built” (Langston and Lauge-Kristensen 2002). Knowledge transfer from the building operation and maintenance team to the build- ing design team is essential for reducing the operation and maintenance challenges that are attributed to faulty design. This knowledge transfer serves to avoid the rep- etition of faulty design that the maintenance team usu- ally encounters during the operation and maintenance phase (Koskela, Huovila, and Leinonen 2002; Jensen 2009). The defects attributed to faulty design are known to cause inefficient use of the property as well as financial losses to the owners through the life cycle of the property (De Silva et al. 2004). Examples of these design defects include control problems, problems with the HVAC equip- ment, missing specified equipment, improper operation of energy management control systems, economizers, and/or variable speed drives that do not run properly, in addi- tion to sensors that do not function properly (PECI 2005). The presence of these design defects would have been © 2014 Taylor & Francis