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Working in the hours of darkness brings its own dangers, but the alert contractor will be well prepared and manage the project with few problems. By Paul Hull |
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Projects worked and completed at night usually are done that way for the convenience of the customer or the general public. A highway project in Denver, CO, will take several years to complete, and much of the work is being done in the hours of darkness to avoid disrupting the congested traffic on Interstate 25. It's that very congestion that the work is scheduled to eliminate. Contractors, then, seldom choose to do their work at night for their own convenience. According to many interviewed, there are normal hazards and challenges that would be less formidable in the daylight. At certain times of the year, however, some contractors like the advantages of night work. "Working at night during the late spring and summer months is often preferable, since there is less traffic and cooler temperatures," observes Harold C. Green, president of Chamberlain Contractors Inc. based in Laurel, MD. Chamberlain has large-scale earthmoving equipment but also handles smaller projects in excavation and grading, such as parking lots. "We have also found it may be easier to acquire materials and our production can be better. There can be less onsite management required too. All those mean higher profitability. The challenge is to package the night work into weekly production segments so that you can schedule crews to work an entire week instead of just one or two nights." Most states do not have laws that say those who work at night are automatically paid more money. If the reality is that workers earn more for night work, it is probably because they are paid more because it is difficult to find qualified, skilled workers who are willing to work the irregular hours. "Doing excavation and grading at night is rare for residential projects," notes Janet Smith, president of ZPSCO Contractors in South Ogden, UT. Smith has extensive experience in field work, planning before the job, and project management. "Residents would not want to be kept awake by the powerful lights necessary for night work. We have never done excavation and grading after the sun sets. For some public-sector jobs, such as concreting bridge decks, the cooler night air is a definite advantage, especially as the concrete itself generates heat, and we have done that most successfully on several occasions. As others have probably noted, there is less traffic disruption at night for that kind of work. When the bigger contractors, like Parsons Construction and Ames, have critical deadlines for their work here, I can imagine they consider night work a necessity." Most contractors with small businesses, especially those whose work is mainly residential, tell us that they seldom, if ever, do night work. We heard that from contractors in communities as far apart and different as Sparks, NV; Forest, VA; Pleasantville, NJ; and Lenoir, NC. "Some communities have ordinances that forbid some construction after dark," notes Bill Estell of Quickway Excavating in Oklahoma City, OK. "I would advise any contractor who is offered night work to make sure that the local authorities allow it." A few mention that they have done night work once in a blue moon, so to speak, but that was a subcontract they had with a prime contractor on a highway or street project. It seems to be traffic and its dangers that constitute the main reason for scheduling night work. "The timing and urgency of a project seem to dictate whether we have to do night work or not," explains Jeff Eldridge at T.J. Lambrecht Construction Inc. With bases in Joliet, IL, and Euless, TX, TJL is one of the nation's biggest specialists in large excavations. "It is the urgency of completing a project at, say, an airport, highway, or landfill that will tell us to do night work." Regarding the key to successful work in darkness, Eldridge points out that good lighting is essential because operating and moving around heavy equipment demands good visibility and concentration for everybody at the site. He adds that his workers seldom attempt anything as precise as fine-grading at night because however good some lighting systems are, they are not quite the same as daylight for such applications. Most contractors seem to agree with that. You're not alone if you choose not to do night work. Sunset Lake Contractors in Newark, DE, says it seldom works at night, mostly because they "do not take on state contracts." At Glen's Backhoe Service in Yukon, OK, the job that is done at night with the company's equipment is clearing the streets when there is a heavy fall of snow and ice. It seems that most night projects are publicly financed and are jobs that would inconvenience the paying public if they were done during the hours of daylight - the normal hours of business and travel. "We've had very few night jobs in the 20 years of my experience," states Jeff Wardell of Skyview Excavation & Grading in Morgan, UT. "The bigger companies involved in road and airport work do work at night sometimes." F.M. Frattalone Excavating & Grading in St. Paul, MN, which is a large company, rarely works at night, says Project Manager Paul Pearson. Ditto for KGM Contractors in Angora, MN, which has multimillion-dollar contracts. The company cites noise and lighting regulations as the biggest deterrents. Health and Safety at Night None of us is a medical expert, so it might be worth reading what health authorities say about people who work consistently at night. From reading the statistics, it can be deduced that night work is not natural for most people, that skills and reactions are not as good as in daylight. Prolonged periods of night work have been possible causes of inferior health, according to some research. In this line of work, the ability to concentrate for hours on end is a key aspect of success, and that skill seems to be more difficult to maintain at those times when others are usually asleep. While this is not intended to frighten anybody, it should encourage watching carefully for any signs of serious fatigue or lack of concentration in our night workers and ourselves. Sleep seems to be the biggest sufferer. Sleep in the day is usually shorter than night sleep, and it is also lighter because there are more external activities and sounds during the day to disturb the sleeper. A worker suffering from poor sleep will tend to become sleepy at the wrong time, and there will be serious concerns about safe performance and efficiency. Have you ever fallen asleep in the armchair during a dull program? Ever almost dropped off while driving your car? Sleepiness affects concentration - something a machine operator cannot afford to lose. If you would like to learn more about sleep patterns and related issues, the phrase to look up or to ask your doctor about is "circadian rhythm." It is a body rhythm with regular ups and downs in the normal day and night. (It might be the reason why some people are "morning persons" or "night owls," with most people being in the middle.) A final thought on this important aspect of night work: It also might affect the worker's social and family life. Lighting
For contractors whose choice is either night work or no project, there are some excellent lighting systems available. Most of us have attended evening concerts or sports events and thought little of the lighting, but there is a difference between watching a night game, waiting to see a home run or snag a foul ball from the stands while chomping on a hot dog, and running an excavator or dozer with precision so that the job does not have to be reworked. No one we spoke to attempted everyday trench construction at night, though a few had been involved in repair work, usually for utilities, that might include some trenching and excavation. Good lighting for nighttime construction work is essential, and there are standards set for the amount necessary - set nationally by the Occupational Safety & Health Administration. You can find those standards, explained and recorded, at the Web site www.osha.gov. It is mandatory that all local standards for lighting and noise be met during any night work. The risks you take by trying to avoid any regulations are not only financial, though they should be deterrent enough; in some communities there is an inspector on-site to make sure you have enough light. The determining factor appears to be the amount of adequate light available for a certain work area, and contractors who have experience in night work tend to learn how much is required and practical and where to find the right lights. If your excavation involves moving along a road, street, or airstrip, for example, you might discover that two trailer-mounted units, hauled along as the work progresses, are enough. Some projects, because of their area and the different jobs going on (e.g., surveying before you excavate), might require more than 20 lighting systems. "Our biggest problem here is mud," observes James Hartt, owner/operator of Hartt's Contracting in Conroe, TX. "We had 18 inches of rain last month, and that can make the excavation and grading difficult. I don't think it would be any more difficult at night, however, because the lighting available now is so good that you can see very well for most applications. I think the main reason that residential customers don't choose night work is the expense. Those lighting systems are good, but they are expensive to rent too." Hartt has three machines as his basic fleet but hastens to add that he can get anything he wants via a good rental store. For the trenches excavated before laying pipeline, night work is not unusual. "We have no problem with it," remarks David Hunt, pipeline installation supervisor for a major pipeline company operating in the western states, who confirms that the necessity for night work is due to the urgency of the need for new pipeline. "We've had a lot of work done for us by Brandon Construction of Powell, Wyoming, and they use lights and never seem to have a problem in speed or precision."
According to Ingersoll-Rand (IR), manufacturers of a broad range of lighting products for North America (and the world), a road-towable lighting tower giving 360º illumination from four 1,000-W halide lamps, mounted on a mast almost 30 in. tall, provides a compact, cost-effective solution for a wide range of temporary lighting requirements. Compact and cost-effective? If your night work is in a confined space, cramped by adjacent structures or work sites, the lighting apparatus must be compact. If your night work is to be profitable, its heart (the lighting system) must be cost-effective. IR also states that this light tower could be ideal for construction and roadwork, as well as for lighting at the scenes of accidents and other emergency situations. The sound pressure level of the unit, powered by a Kubota diesel engine, is 63 dB(A) at 23 ft. The mast can be rotated a full circle in 90º steps, lockable at each point. One other aspect of this light tower that IR emphasizes is the simplicity of the controls (and the panel includes an engine hour meter, especially useful for rental customers and stores). Two portable light towers introduced by Allmand Bros., based in Holdrege, NE, are equipped with larger generators that allow the units to power other auxiliary equipment. The Allmand 15330 and 20330 have 15- and 20-W generators that give enough capacity to provide power for temporary work trailers, power tools, and/or additional lighting at the site. This manufacturer says its exclusive SHO lighting system generates up to 50% more lumens per fixture than competitive light towers, and the two models mentioned might have six- or four-SHO fixture configurations. A feature that interested us was the Saf-T-Visor attachment that reflects (hitherto wasted) light directly onto the work site. An 1,800-rpm, 32-hp Isuzu 4LE1 liquid-cooled diesel engine powers the light towers, and there is a polyethylene fuel tank (removable) to permit many hours of continuous service. Allmand's light towers have a four-point outrigger system, with captive latches rather than those awkward pins, and its center-mounted tower assembly provides stable operation in windy weather. The user can tow the towers with Allmand's SHO parallel lamp fixtures installed; that should reduce setup time and avoid damage during travel or lamp removal and replacement.
An electrically operated lamp-tilting system (called PowerTilt) is a feature of the light towers from England-based Sandhurst Manufacturing Company (SMC). The system is an option on the manufacturer's Telelight TL-35 light tower and enables users to simultaneously rotate the tower's four 1,000-W metal halide lamp heads electrically from a vertical to a horizontal plane. SMC also claims to be the first to provide Full Bunding, a design change that incorporates a fully bunded unit within the body shell of the lighting system to contain all diesel and oil spillage. That eliminates ground contamination. What about the noise? Anything run by a diesel engine makes noise, and that is a sensitive aspect of any night work. The supersilent operation of SMC towers means there is extensive baffling of the exhaust and the use of acoustic sound-deadening foam to reduce noise output, claimed by SMC to be the lowest level worldwide for a standard production set. Complementary to good lighting are good clothes, jackets, hats, and pants that can be seen at night. Reflective clothing is not as expensive as you might imagine if you've never investigated its benefits and styles, and it will certainly help you to comply with regulations about visibility of workers. Equipment After Midnight
Loaders don't start growling and dozers don't suddenly lurch across the site after midnight, although it might seem that way to unprepared operators. The equipment used by contractors for night projects is the same they use during the day, with the obvious addition of lights. From what many contractors say, they have work lights on their machines anyway because most of them live in states and counties where the weather isn't perfect, where dark clouds can make even the daylight dangerous, where twilight comes too soon as the fall approaches, and dawn too late. Experienced workers say they are more careful, probably slower, at night. A sentiment shared by many is that nobody they've ever met prefers to work at night since the hazards are greater and the probability of mistakes is higher. Somewhat surprising is the large number of contractors and workers who have never worked at night, which they are pleased about. We have seen reports of excavators working 24 hours a day, with breaks for maintenance and changes of operators for each shift. The machines themselves do not know if it is day or night (not yet, anyway!), and the person in the cab becomes even more important when the sunlight goes. Visibility from the CX Series of excavators from Case was improved with 14% more glass, giving what was described as a panoramic view of the work area. The entire cockpit slides forward for better visibility into the excavated area, and the exclusive, lower right window provides a clear view of the track for easier positioning (and loading onto the trailer after the job). Features such as zero tail swing and compact maneuverability seem more important at night. Take the Bobcat 442, for example. It's the biggest excavator from that manufacturer. "The 442 offers an alternative to 14-foot tractor-loader-backhoes and 20,000- to 25,000-pound excavators," notes Tom Connor, Bobcat excavator product representative. "You can work faster and easier on bigger jobs where space is scarce. You can take on excavating jobs alongside walls, fences, or other obstacles and still load a truck parked right behind the excavator." If one of the goals of night construction work is to have as little confusion and comings-and-goings of machinery as possible, then it seems practical to determine beforehand how small an excavator, loader, or dozer you can use. For some applications, however, a large excavator that does not have to move from its original position (and is not a constantly moving hazard) seems a good idea. What does the new Komatsu excavator with near-zero tail swing allow you to do? It lets you minimize the workspace and operate in confined workplaces that might be inaccessible to machines of similar capacity but that don't have the advantage of the zero tail swing. On a road or street project, for example, an excavator such as the Komatsu PC138USLC-2 can load within its track width and requires only one traffic lane for its maneuvers. It simplifies construction and utility work in narrow urban areas. In addition to the excellent maneuverability, the excavator still offers 20,940 lb. of bucket digging force and 13,890 lb. of arm force. This excavator's compact design not only saves space but it can reduce concern for damage to the environment (such as trees) and other machines at the work site. Even the door saves space; it opens along the exterior curve of the cab rather than swinging out on hinges that would move it beyond the tracks. Its noise levels have been reduced to 72.5 dB(A) with hydraulics over relief. In an interesting association of ideas, one western state contractor told us he had asked a mining friend about equipment for night work because the friend had praised Komatsu machines in tunnels (which are similar to night sites). Many of us, then, might rarely - if ever - have to organize crews and machines for night work. It is comforting to know, however, that the right equipment is readily available for purchase or rent - to turn the night into virtual daytime. Our greatest concern will be the conduct and efficiency of our crews because, however much they assume that one part of the 24 hours is the same as another, statistics show that there are different stresses and strains at night. They are manageable, but they do exist, and we should be aware of them before the job starts. Paul Hull writes on construction and environmental topics for several international magazines.
GEC - March/April 2003
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