Khairulzan Yahya

Using life cycle assessment for estimating environmental impacts and eco-costs from the metal waste in the construction industry

Purpose – The purpose of this paper is to investigate how to estimate the ecological costs form metal waste based on life cycle assessment (LCA) environmental impacts generated from the management of the construction waste. Design/methodology/approach – LCA methodology and eco-indicators 95 were used to calculate the impact from metal waste based on three waste management strategies. Findings – The results of this study establish that the ecological impact from metal waste management is mainly due to the burning of diesel from machinery during the dismantling processes and the use of vehicles for transportation. The results proposed equations and curves for estimating the ecological cost from metal waste based on waste management strategies. Research limitations/implications – The research could affect members of the engineering and construction industry, since it provides methods for costing the ecological impact from construction waste. The eco-costs will assist in implementing sustainable strategies th...

Noise Produced By Transverse Rumble Strips: A Case Study on Rural Roadways

Transverse roadway strips (TRS) are a common approach used by the local authorities in Malaysia for the purpose of road safety on rural roadway. However, there were complaints made by residents about the excessive noise pollution produced by TRS. The objective of this study was to evaluate the external noise produced by the application of TRS, to evaluate and to anticipate the annoyance response due to installation of TRS. The investigations were carried out through the changes of noise level indices, estimation of the annoyance response using the traffic noise index (TNI) and anticipation of resisident response anoyance. Measurements of the external noise level produced by the TRS were taken for two hours at two location with and without TRS. Results showed that TRS increased the equivalent noise level, LAeq1hour, L101hour and L901hour by as much as 14 dB(A), 16 dB(A) and 9 dB(A) respectively. TNI values also increased as much by as 42% and exceeded the suggested value for planning purposes of 74 dB (A) for 3% annoyance from the social surveys. This investigation shows that TRS noise has a very strong impact on the community and this was the reason behind the complaints made by people living in study area.

Probability Approach for Prediction of Construction Site Noise

Abstract This paper describes an alternative method of predicting noise from construction sites using a probability approach. The basis of the approach is the separation of the source characteristics from the propagation characteristics. A site area is divided into a number of square patches in which the source can be located at the centre of any patch or node. The approach assumes that the probability that the noise source of certain acoustic power is at a particular node is the same as for all other nodes. The noise level from each patch is obtained and the temporal noise level distribution during the working day period can be constructed. LAeq accompanied with standard deviation and noise indices during a working day period can be estimated. The effect of the duty cycle of equipment and number of items of equipment were incorporated in the approach. When validated with the current procedure, the model LAeq value has good agreement with those obtained from BS 5228, and thus indicates that the probability approach is capable of predicting the equivalent noise level. The method could be used as the basis of an operational management tool for a noise abatement scheme.

A Stochastic Simulation Framework for the Prediction of Strategic Noise Mapping and Occupational Noise Exposure Using the Random Walk Approach

Strategic noise mapping provides important information for noise impact assessment and noise abatement. However, producing reliable strategic noise mapping in a dynamic, complex working environment is difficult. This study proposes the implementation of the random walk approach as a new stochastic technique to simulate noise mapping and to predict the noise exposure level in a workplace. A stochastic simulation framework and software, namely RW-eNMS, were developed to facilitate the random walk approach in noise mapping prediction. This framework considers the randomness and complexity of machinery operation and noise emission levels. Also, it assesses the impact of noise on the workers and the surrounding environment. For data validation, three case studies were conducted to check the accuracy of the prediction data and to determine the efficiency and effectiveness of this approach. The results showed high accuracy of prediction results together with a majority of absolute differences of less than 2 dBA; also, the predicted noise doses were mostly in the range of measurement. Therefore, the random walk approach was effective in dealing with environmental noises. It could predict strategic noise mapping to facilitate noise monitoring and noise control in the workplaces.

Bio-composite materials potential in enhancing sustainable construction

AbstractAccording to the sustainability principles, building should have zero-embodied energy in order to minimize the amount of carbon. In previous practices, construction materials have been composed with non-recyclable materials and after demolition of buildings the debris were put on different landfills. Nowadays, most of the material manufacturers have shifted their concerns to produce materials by using renewable resources, and also gained opportunity in utilizing wasted streams. The proposed biomaterials have been produced using natural fibers which reinforce biodegradable polymeric, in which naturally occurring aliphatic thermoplastic polyesters are produced by microbes via bacterial fermentation in carbon-rich environments. The composite material produced exhibits comparable properties to structural grade wood and is rapidly biodegradable in specific anaerobic conditions, at the end of its useful life. Using anaerobic digester sludge from local wastewater treatment plants as the biodegradation me...

An overview of knowledge management (KM) issues for implementation in consultant firms in Malaysian construction industry

In the past few years, there has been a growing interest in treating knowledge as a significant organisational resource. Thus, effective development and implementation of KM requires a foundation in several rich literatures. As a preparation for the competitive industrial nation, KM is an important countenance that should be the point of convergence for the industry players. This paper wishes to draw the attention on the current situation of KM practice, focusing on consultant firms in Malaysian construction industry. Questionnaires were distributed to about 200 respondents working in the industry, with the objective of appraising the KM implementation amongst consultant firms working in construction industry in Malaysia. This paper also gives the overview on KM definition, process, understanding and challenges in construction industry, besides the critical success factor of KM implementation. The literature is restricted on the recent KM study of 17 years research from 2000 to 2017. Finally, this paper proposes the conceptual ideas of relationship between KM process, KM understanding and KM challenges with critical success factor of KM implementation.

Disparities in Generated Noise Between Predictions and Measurements from Construction Sites

In order to avoid excessive noise exposure and to improve construction environmental performance, noise should be predicted at the planning stage and appropriate mitigation measures should be implemented. There are various noise prediction methods that have been practiced by the respected parties. The simplest and most recommended method of noise prediction is the procedure of BS 5228-1:2009. However, previous studies have claimed that this method was inaccurate because of several factors. Therefore, this study attempts to assess the difference between the prediction using this method and the noise obtained from the measurement. The study was conducted by measuring noise emissions from earthwork, piling work and structural work at selected measurement stations, investigating the individual noise emission of construction equipment and predicting construction noise using the measured data. Several related variables were also measured to identify their effects on outdoor sound propagation. The results of t-test showed that all the stations have the significant disparities between prediction and measurement. The highest over prediction of 5 dBA was due to the use of several moving machines during operation processes and high noise emission level of machines. Consequently, this affects the distance between the sound source and the measurement station (geometry factor).

Noise Exposure among Machine Operators on Construction Sites in South Johor, Malaysia

Machines operators expose to excessive noise in the workplace that may lead to hearing damage. This study investigates construction machine operators noise exposure levels for eight hours or time weighting averages (TWAs), relationship TWA with machine noise emission level, the practices of using hearing protection devices (HPDs) and working in a closed machine cab. Heavy and non-heavy machine operators at five construction sites involved with excavation and piling activities were selected and measured by using dosimeters. 68% of operators were exposed to TWA of 85 dBA and 18% of the operators exceeded the permissible limit. 40% of operators work inside a closed machine cab, 18% wear earplugs and only 16% practiced both. Both operators of heavy machines (except excavators) and dump trucks are exposed to TWA > 90 dBA if they work in open machine cabs. The TWAs were found well correlated (r=0.41) with the machine noise emission, which ranged between 84 dBA to 125 dBA. Furthermore, this study proposes the type of HPD for the operators of typical machine to minimise the risk of hearing loss.

Evaluation of external noise produced by transverse rumble strips on rural roadways

Transverse rumble strips (TRS) are widely used by local authority in Malaysia to reduce vehicle speed and alert drivers to any changes on the road. The objective of this study was to evaluate the anticipated community reaction due to the external noise produced by the TRS. The evaluations were carried out through the noise levels measurement, calculation of the TNI and anticipated community response analysis. Measurements of noise level were taken at two locations of a rural roadway that have received complaints from the public i.e Kampung Pengkalan Raja (KPR) and Kilometer 52 (KM52) of Johor Bahru-Pontian federal road, in Pontian District, Johor. Results showed that TRS can increase the level of traffic noise, TNI values, and annoyance response in community. TNI values of 126dB(A) and 119dB(A) for KPR and KM52, respectively were exceeded suggested level of TNI for planning purpose of 74 dB (A) for 3% annoyance from the social surveys. Anticipated annoyance response analysis also indicated that resident in both locations received strong to very strong impact that can lead to vigorous community reaction and this was in agreement with the real reaction from the community.