導入建築資訊模型於空調設備工程成本估算之實證研究

Abstract

建築資訊模型(BIM)是未來營建業的一大趨勢，目前國內已有部份公共統包工程要求導入BIM，無論在能源分析、不同專業之間的協同作業、衝突檢測以及物料數量輸出等都有可觀的成效。然而在業主沒有要求的情況下，機電顧問對於主動使用BIM普遍採取消極的態度，設計方式從傳統的二維圖說轉換到建築資訊模型，技術的學習與適應皆需付出一定成本，導入BIM的意願低下也同時限制了BIM在工程數量與估價功能的發展。然而在機電顧問對空調系統工程編列的成本當中，有部份項目採取乙式計價或槪算的方式，導致數量與成本與實際有落差，業主也無法掌握所有成本的來源依據。因此本研究希望透過實證研究的方式，利用BIM軟體Revit 2014對已完工案例建置模型，在過程中分析軟體的使用性，以及輸出更明確的數量並與合約數量與金額比對，找出差異產的的原因，並對數量與成本的計算方式作檢討。 本研究透過對高雄市南部災害應變中心之空調系統建置BIM模型，輸出更明確的空調系統實體設備及管線數量，以分析BIM於機電工程數量及成本計算之效果，把機電工程空調系統中的部份槪算項目提升為細算項目，期許幫助業主利用BIM取得更詳細真實的機電工程成本，提升業主對機電顧問之信任程度，並推動BIM作為機電工程設計工具之應用。根據本研究結果，BIM在空調系統估價功能與模型繪製功能上尚有需要改善的地方，本研究透過BIM輸出空調系統總金額為10,036,565元，所對應之項目總合約金額為10,439,618元，結果顯示模型輸出之成本較合約原始金額低，差距為403,053元，差距為-3.9%，發現差異來源主要來自於管線長度與管另件，透過各項明細之結果分析以及探討傳統機電工程估算方式發現，過去機電顧問有高估槪算項目金額的傾向。

Building information modeling (BIM) is considered as a major trend of the construction industry in the future. Some owners have required implementation of BIM to help improve collaboration between different professions, conflict detection and material quantity takeoff (QTO), etc. However, the development of BIM in cost estimation is still limited by the negative willingness of the consultants to use BIM as a design tool for buildings because of the cost and time to adapt the new technique. In traditional way to estimate the cost of the HVAC system in buildings, a part of the total cost is evaluated as a rough approximation, as known as lump sum, instead of detailed calculation and that leads to an inaccurate cost and making the origin of it invisible. The research aims to build the building information model of a completed public building and clearly export the detailed quantity and cost of the items which can only be budgeted approximately in traditional estimation method. By the process of modeling and comparing the numbers of both the BIM method and traditional method, verified the availability and accuracy of BIM QTO and cost estimation of HVAC system. One of the purposes of this study is to promote BIM to the owners and MEP designers. After a thorough investigation into the parameter setting of the BIM software, some limits in the cost estimating capability of the software were found and it shows that the software is still waiting to be perfected. However, by building detailed HVAC system components of a completed public office building, overestimation of HVAC budgets has been found and leads to contractors’ extra profit equivalent to 3.9% of the total cost of all the built items in the building information model.