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Fulltext Egress modeling in performance based fire engineering design–fire safety study at NIOSH Tower

Hari Krishnan Tamil Selvan, Raemy Md Zein, Mohd Abd Muiz Che Abd Aziz, Noorul Azreen Azis

Journal of Occupational Safety and Health, 2015;12(1):41-44.
MyJurnal

Evacuation profile systems in high rise building are important to determine the safety level during any fire
emergency. In relation to this, the study was conducted with its objective to develop the evacuation profile for
NIOSH Tower. Evacnet-4 software was used to develop models for building evacuations using the building network
descriptions and the initial content of the occupant at the beginning of the evacuation. The results show that it
requires 390 seconds to evacuate NIOSH tower, with the highest number of bottlenecks recorded for the Third Floor.
Identification of bottleneck is important to determine the evacuation periods. The information gained from the model
may be used for the emergency response planning and for support material. The model should be tested in real time
to have its reliability verified.
A study of the effectiveness of local exhaust ventilation (LEV) using computational fluid dynamics (CFD) approach

Ng, C. S., Leman, A. M., N. Asmuin

Journal of Occupational Safety and Health, 2012;9(3):1-8.
MyJurnal

Local exhaust ventilation (LEV) is used in industries to capture contaminants such as gases, dusts, mists, vapours or fumes out of workstations to protect occupants’ exposure to contaminants. LEV is allocated and installed by employers, however it doesn’t work accordingly. LEV design is often overlooked and underappreciated. Effectiveness of LEV system can be achieved if more attention is focused to proper design of LEV system. To solve this issue, computational fluid dynamics (CFD) can be performed. CFD is a software tool to predict and simulate fluid dynamic phenomena. CFD is used to forecast or reconstruct the behaviour of an engineering product under assumed or measure boundary conditions. However, CFD is just a prediction tool, which can lead to inaccuracy of predicting airflow due to problems with pre-processing, solver and post-processing with parameter from actual experimental results. Therefore, validation is needed to help minimizing percentage error of CFD methods. In this research, measurements of airflow parameter of LEV system at National Institute of Occupational Safety and Health (NIOSH) Bangi, Selangor were conducted. Control Speed panel found at NIOSH Bangi, which is used to increase or decrease speed of fan, was performed using Control Speed of 20%, 40% 60% and 80%. Upon validation, average absolute error obtained from four different control speeds ranges from 3.372% to 4.862%. Validity of CFD modelling is acceptable, which is less than 5% and good agreement is achieved between actual experimental results and CFD simulation results. Therefore, it can be concluded that CFD software tool can be performed to simulate air velocity in LEV system. CFD methods can save labour costs and time consumption when it is used during earliest stage of LEV design, before actual construction is implemented. The outcome of this paper can be used as a baseline for factories equipped with LEV system to protect occupants’ exposure to contaminants.
Background level of microbe in new office building

Ahmad Sayuti Zainal Abidin, Leman, A.M., Nor Mohd Razif Noraini

Journal of Occupational Safety and Health, 2011;8(2):25-34.
MyJurnal

This study was done to investigate the background level on microbiological indoor air pollutants in new constructed 8 stories buildings (2 level of Hostel facilities, 3 level of Training Room level, 2 level of Offices and 1 Exhibition Halls and Rooms) in Bandar Baru Bangi, Selangor. The offices and exhibition hall are carpeted furnished. All these spaces were using centralized air conditioning system. Airborne microbes’ concentrations were determined by using a single stage impactor (Biosampler) as per requirement of National Institute of Occupational Safety and Health NIOSH method NIOSH Manual Analytical Method MAM 0800. Mean concentration of total bacteria detected is 1351 CFU/m3 and it was found significantly higher compared to maximum exposure limit 500 CFU/m3 in office room. The mean concentration of total fungi in the office rooms is 479 CFU/m3 and it was found slightly lower compared to maximum exposure limit 500 CFU/m3. The airborne microbe levels were found slightly lower in the accommodation, training and exhibition rooms compared to office room. These findings indicate that although a new constructed building should be having a significant background level of airborne microbe (total bacteria and total fungi).
Safety in the construction industry: are we barking at the wrong tree?

Khairuddin Sulaiman, Norhayati Mahyuddin

Journal of Occupational Safety and Health, 2005;2(1):30-36.
MyJurnal

The construction industry is an important industry in the Malaysian’s economy. Much has been said about the quality of the product as well as the image of the industry due to the small percentage of local workers on site. The industry’s welfare and safety record is not at all encouraging. To stop the rot, the government has taken important and significant steps by the establishment of the Malaysian Construction Industry Development Board (CIDB) and the National Institute of Occupational Safety and Health (NIOSH). These efforts have shown some significant positive improvement in the perception and action of those involved in the industry but we are still far from the standard shown in other developed countries in terms of site safety. This paper is to discuss the roles and responsibilities of the key players in the industry be it the clients, consultants or contractors. The focus is on the ‘upstream’ activities i.e. the pre-construction stage, rather than the ‘downstream’ i.e. the construction phase of a project.
Fulltext Comparison of direct method and indirect methods for sampling and analysis of airborne respirable crystaline silica by X-ray difractometer

Suhaily Amran, Ahmad Sayuti Zainal Abidin, Shoffian Amin Jaafar, Mohd Talib Latif, Abdul Mutalib Leman

Journal of Occupational Safety and Health, 2015;12(1):137-141.
MyJurnal

There are several alternative sampling and analytical methods available for the determination of respirable
crystalline silica exposure among workers. The commonly used ones are, (1) NIOSH Manual Analytical Method
No.7500(NMAM 7500) which is Silica, crystalline, by X-ray difractometer via filter deposition(NIOSH 2003), and
(2) MDHS 101 (Methods for the Determination of Hazardous Substances (MDHS) Guidance No.101: Respirable
crystalline silica in respirable airborne dust). The aim of this study is to compare applicability of respirable crystalline
silica sampling and analysis between method MDHS 101 and NMAM 7500. Laboratory procedures will be performed
strictly based on MDHS 101 and NMAM 7500. Both methods apply X-ray diffraction as analytical technique with
many variations on sampling techniques and laboratory preparations. Quality assurance values such as detection
limits, accuracy and precision are derived from both data and will be compared to determine which of the method
establishes better quality assurance. The method which establishes better quality assurance will be recommend to be
used in Malaysian respirable crystalline silica monitoring programme. The strength of this research lies on its potential
to provide local capabilities in analysis of respirable crystalline silica in Malaysian setting.
Comparison of indoor air contaminants in different stages of new building occupancy: Training and office setting

Nor Mohd Razif Noraini, Leman, A.M., Ahmad Sayuti ZainalAbidin, Ruslina Mohd. Jazar, LailaShuhada Mat Zin, Rasdan Ismail, et al.

Journal of Occupational Safety and Health, 2012;9(3):31-38.
MyJurnal

This study has been conducted in a new constructed building of NIOSH Malaysia located at Bandar Baru Bangi, Selangor. The goal of the case study is focusing on the level of Indoor Air Contaminants (IAC) including chemical contaminants within three consequent stages which are before furniture install, after furniture install and during one month occupancy. This study was divided the sampling area into two main facilities which are training and office setting. The contaminants has been measured consist of sixparameters such as Carbon Dioxide (CO2), Carbon Monoxide (CO), Total Volatile Organic Compounds (TVOC), Formaldehyde, Respirable Particulates (PM10) and Ozone. The result of Carbon Monoxide (CO), Total Volatile Organic Compound (TVOC), Respirable Particulates (PM10) and Ozone show an increasing trend across the three sampling stages. The Formaldehyde show an increasing trend in the first and second stages but were reduced significantly the last stage of sampling. These finding indicates that furniture and fittings installed might be a potential sources of indoor air contaminants. The management should be aware to their indoor air status to protect the occupant from the risk of unwanted exposure especially during the early stage of building occupancy.
The effectiveness of applying different permissible exposure limits in preserving the hearing threshold level: a systematic review

Sayapathi BS, Su AT, Koh D

J Occup Health, 2014;56(1):1-11.
PMID: 24270928

OBJECTIVES: A systematic review was conducted to identify the effectiveness of different permissible exposure limits in preserving the hearing threshold level. This review compared the limits of the US National Institute of Occupational Safety and Health with those of the US Occupational Safety and Health Administration. The prevalence of occupational noise-induced hearing loss is on an increasing trend globally. This review was performed to reduce the prevalence of noise-induced hearing loss.
METHODS: We searched 3 major databases, i.e., PubMed, Embase and Lippincott Williams & Wilkins Journals@Ovid, for studies published up until 1May 2013 without language restrictions. All study designs were included in this review. The studies were identified and retrieved by two independent authors.
RESULTS: Of 118 titles scanned, 14 duplicates were removed, and a total of 13 abstracts from all three databases were identified for full-text retrieval. From the full text, eight articles met the inclusion criteria for this systematic review. These articles showed acceptable quality based on our scoring system. Most of the studies indicated that temporary threshold shifts were much lower when subjects were exposed to a noise level of 85 dBA or lower.
CONCLUSIONS: There were more threshold shifts in subjects adopting 90 dBA compared with 85 dBA. These temporary threshold shifts may progress to permanent shifts over time. Action curtailing noise exposure among employees would be taken earlier on adoption of 85 dBA as the permissible exposure limit, and hence prevalence of noise-induced hearing loss may be reduced.