Blowing Hot And Cold

Nick Campey from Watkins Hire explains the best approach to keeping the site office warm in winter, cool in summer and dry all year round

If there is one thing that quarry operatives are used to as part of their everyday work, it is dealing with whatever the weather has to throw at them. Being prepared to get the job done come rain or shine may be part of the on-site team’s job description, but the quarry’s management team has a duty of care to ensure that the site office provides a place in which to warm up in winter, cool down during hot summer weather and dry out all year round.

The heat is on

The reality of working on site at a quarry is that the site office is likely to be basic. However, just because the office is a prefab does not mean that it should fail to offer the levels of comfort that professionals would expect from a more permanent base. Any office environment is legally required to be heated to at least 16°C and, although most site offices will have heating of some kind, it is seldom powerful enough to heat the office effectively if the external temperatures drop significantly. As a result, offering adequate heating that is both efficient and instantaneous can be a challenge during the winter months, and the most effective way to overcome this challenge is with the help of temporary equipment hire.

Small, portable, electric heaters offer a low-cost and flexible solution to the problem of cold and draughty site offices; these can be delivered to site within hours and warming up the office just minutes later. Designed as a plug-and-play solution for any environment that needs rapid, safe heating, this type of heater simply plugs into an ordinary 13-amp socket and heats up quickly to provide a warmer environment. This means that there is no requirement for a temporary generator or for complex wiring that could pose a health and safety risk. It is also important that the heater selected should be fume free, as it will be operational in a relatively small, enclosed space.

A 3kW electric heater should be sufficient to provide the heating required by a quarry site office, even in the harshest of winter weather conditions. By selecting a heater with an up-rated air-moving system, such as the Watkins Hire KwikHEAT, the user can ensure that they gain the most effective heating output for the size of unit. The unit should also be fully portable so that it can be positioned in an appropriate location for the site team. For even greater flexibility, a stackable heater design, such as the KwikHEAT, will provide the possibility of installing additional heaters should these be required, without taking up any more of the usable space inside the cabin.

Keeping cool

Similarly, during periods of extremely hot weather, hiring an air-conditioning unit as a temporary measure to give staff some respite from the heat is also advisable from both a health and safety and a productivity perspective. While there is no legal maximum temperature for the working environment in the UK, the World Health Organisation (WHO) advises that people should not be expected to work in temperatures higher than 26°C. This temperature level is further supported by the UK Government’s own ‘2009 Heatwave Plan’, which gives advice on reasonable and safe maximum working temperatures. Research certainly suggests that working in very hot temperatures affects concentration and productivity. Moreover, the very nature of quarries means that staff are often particularly vulnerable to the heat when there is a heatwave. The combination of exposed location, reflected heat from the rock face and a lack of breeze in a sheltered quarry void means that temperatures should be monitored very carefully and fast action taken to alleviate the heat as it starts to rise.

As with heating, the answer lies in hiring lightweight, portable air-conditioning units that can plug straight into an ordinary 13-amp socket and be fully operational within minutes of arriving on site. The Watkins Hire KwikCOOL 8 unit is an example of just how flexible and convenient this type of equipment can be. Offering A-rated energy efficiency and operated either by touch control or remote controller, the KwikCOOL 8 weighs just 29kg and can cool an area of up to 45m3. The unit is provided with 1.5m of flexible ducting so all the user needs to do is plug it in, find an outlet for the ducting (a door or window) and switch it on for instant cooling.

This type of unit can also provide heating and de-humidifying, making it a popular choice for long-term rental or purchase. However, as heating and cooling may only be required for short periods during the year, it may be more cost-effective to hire individual, specialist items of equipment as and when the need arises.

Drying out

While some air-conditioning units may also have a de-humidifier function, the amount of wet workwear that passes through a site office often requires something more powerful. If wet clothing is continually left to dry in the site office or its boot room without the aid of a de-humidifier, the room will gradually become damp and not only will this prevent the clothing from drying out properly, it will also impact on the efficiency of the cabin’s heating.

Once again, portability and flexibility are key requirements when deciding on the best de-humidifier for the job. For example, the Watkins Hire KwikDRY 60 is lightweight and has been designed with 25cm wheels to make it easy to manoeuvre. Like the heating and air-conditioning solutions, it is easy to operate and can simply be plugged into a 13-amp socket and put to work immediately. Once operational, a green light indicates when it is working normally and a yellow light indicates when its 14-litre capacity tank is full. This is then removed and emptied to allow the equipment to become fully operational again.

Small but essential

Compared with the earthmoving and processing equipment usually found at quarry sites, portable heaters, air-conditioners and de-humidifiers may seem somewhat peripheral. They are, however, an essential element in providing a fit-for-purpose work environment for quarry operatives. By contacting and working with a hire firm before any need for heating or cooling equipment arises, the right type of kit appropriate to the site can be identified in advance of changes in the weather.

Letters to the Editor

Sir, —  Further to the article in the January issue of QM about heating and cooling site offices, for some years now I have been suggesting to quarry operators that they should try using heat from the ground to heat their offices, workshops, control cabins etc. So far as I know the idea has not been taken up, although I do recall that some years ago one firm did experiment with getting heat from quarry ponds, but I did not hear the outcome.

By their very nature, quarry operators often have readily available drilling equipment and drilling expertise and suitable small sites with favourable ground conditions close to buildings where ground-source heating, or even cooling, could be used; the technology of the reversible heat pump is already well established.

There is a ready supply of free heat in the ground, the only costs involved being the setting up of a low-tech recovery system at relatively shallow depth and the installation of a heat pump with its associated pipework and control system – all technologies that our industry is using every day. Some electricity will be needed to run the pump and there will also be some maintenance costs, but overall returns should be positive.

While such a system would have difficulty in rapidly catering for a sudden cold snap, such as the one we have experienced recently, and would not eliminate the need for the heating and cooling systems described in the article, it would go a long way towards saving on the regular energy costs of running such systems.

I would be interested to hear from QM readers as to whether any ground-source heating systems have been tried at quarries. It would seem that significant energy could be saved if such systems were introduced widely within the industry. For anyone interested in knowing more, the Environment Agency has prepared a useful report on the subject.

Yours etc,
Dr CLIVE NICHOLAS, FIQ,
Exeter

Sir, – Dr Clive Nicholas, in his letter published in the March 2010 edition of QM, refers to the use of ground-source heating and cooling within the quarrying industry. The industry is indeed an excellent sector for the development of this technology in the UK.

The probable introduction of the Renewable Heat Initiative in April 2011 will provide large financial incentives for the generation of renewable heat sources. The use of naturally occurring low-grade heat, which is easily exploitable during the life of a quarry and, more importantly, offers a long-term sustainable source of energy that is potentially revenue generating post restoration, makes ground-sourced heating and cooling an extremely attractive technology.

An article on this subject was published in the December 2009 edition of Mineral Planning magazine and a paper has been submitted for consideration at the EIG 2010 conference in Portsmouth. I would be happy to provide any reader with more detailed information.


Yours etc,

JAMES DODDS, MIQ
JDIH Envireau,
Cedars Farm Barn,
Market Street,
Draycott DE72 3NB.