In an age of daring architectural shapes, imaginative use of materials and cutting edge construction techniques, you might expect that specifying a horizontal access hatch is a skill which the construction industry had honed and refined decades ago. Strangely, this is not the case and we still have some way to go. But Bilco is working on this, as General Manager James Fisher explains.
Horizontal access is an important feature in any sizable building, including commercial offices, retail destinations and multiple occupancy residential properties. This applies to public buildings such as museums, hospitals and prisons, as well as luxury properties such as spas, hotels and leisure facilities. But although a huge proportion of the built environment, apart from single dwelling housing, requires access products, surprisingly little construction industry expertise has been developed in specifying them.
The problem has largely been one of the ownership of the specification of these products. Architects, who are understandably more absorbed with the look and finish of the building, frequently still mark a square on a roof plan for a roof hatch, but do not specify an actual product; or even a specific size. The specification is often left to the M&E contractor; sometimes to the facilities management company, if in place during the building process; and occasionally to the roofing contractor. By the time the product is actually specified, the square marked on the plan may be taken to be the actual size required, or it may be left open to interpretation. This is less than desirable, because it opens the door for price, rather than quality and purpose of use, being the deciding factor for the specification.
Increasingly, roofs are used to locate some of the equipment which serves the building. Heating and ventilation equipment such as air conditioning, boiler rooms and now, more commonly, air source heat pumps are often located on the roof. Telecoms equipment is also often sited on a roof, as is window washing equipment and lightning protection. All of this must be regularly inspected and maintained, making safe access to the roof essential.
The first question that the specifier of a roof hatch must ask is the purpose of the access. There are five main types of access to a flat roof.
- Personnel access for infrequent access
- Personnel access for frequent access with a toolbox
- Personnel access for frequent access with a toolbox and small equipment
- Equipment access
- Ladder on the outside of the building
Due to the confusion as to whose responsibility it is to specify, although these uses are all quite distinct and clear, much of the expertise in specifying appropriate products for each application has remained with the manufacturer.
This has not been helped by the fact that there is to date no industry standard for the performance of a roof hatch, so there is a great deal of variety from manufacturer to manufacturer, making it more difficult for the specifier to compare like for like. Some manufacturers produce cheaper products, while others invest more in quality and safety, which can come at a premium, but will be safer and, indeed, last longer in the long run. There is also very little guidance for the interface between the roof hatch and the use of a ladder. There is a recommendation from the HSE that three points of contact should be maintained when using a ladder, but at the point at which a user passes through a roof hatch, this can be difficult to maintain.
Safety is of the essence in all of these situations, and should therefore have a significant influence of product specification. Cost will always be one factor in specifying an access hatch, but thought should also be given to how the product will be used in the future. In the past, in cases in which an inappropriate product has been specified – and this is often from a noble desire to obtain value for money – an ongoing safety problem has been inadvertently created. This is a situation which the building owner or occupier will have to live with, or may have to rectify in the future. They inherit a health and safety issue which a little more thought could have avoided.
The ladder on the side of the building, for example is now increasingly recognised as being less likely to be the ideal situation for any relatively tall building. To begin with the ladder itself can compromise security, issuing an invitation to unwanted potential intruders to access the building from above. However, perhaps more seriously, if this is the only mean by which the roof can be accessed, it represents a very tall, hazardous climb for personnel and is problematic for transporting tools and equipment to the roof. A far safer option is to access the roof from the top floor of the building via an access hatch and a shorter ladder. This restricts the potential distance to fall and immediately reduces the health and safety issue.
The frequency of use of the roof hatch and, just as importantly, what needs to be transported through it should be the next consideration. Depending on how the roof space will be used, attention should be paid to whether the roof access should be via a permanent set of stairs, a fixed ladder, a retractable ladder or even a mobile ladder. This last option, a mobile ladder, should be the last resort. We know statistically that fixed ladders are inherently far safer than mobile ladders, and they do not require ‘footing’ by a second person to make them secure.
The hatch itself may be a standard size or may need to be manufactured to a bespoke size. In many cases, a standard size will be perfectly suitable; but, due to a lack of specification at the building design stage, we have often noticed a bespoke product being ordered where a standard size would have been perfectly sufficient. This can push up the cost of the roof hatch and makes it tempting to opt for a cheaper manufacturer, rather than for a quality product.
How often tools and equipment will need to be transported through the hatch is a key consideration. So is the safety of the person as they pass through the hatch. Safety should encompass a number of things. Firstly, opening and closing the hatch will require the operative to take at least one hand off the ladder in order to operate the hatch. It is essential that they can keep the other hand on the ladder in order to steady themselves. To maintain balance it should also not be difficult to open the hatch. Hatches which require two hands and a lot of effort to operate are inherently less safe.
It is equally important, that once opened, the hatch will stay open and not blow shut on the operative. This is also important for the hatch itself, as slamming shut due to a gust of wind will also damage the hatch and shorten its useful life. We have invested a great deal in this area of development and we use compression springs to keep the hatch open, whereas some other manufacturers may favour gas struts. Although cheaper, these are not as robust, do not withstand windy conditions as well and often have a shorter lifespan as a result.
Where permanent stairs are not needed for frequent moving of equipment, maintaining three points of contact on the ladder is essential. At the top of the ladder, at the point of egress, the height of the last few rungs makes it impossible to maintain a hand hold on the ladder itself, making passing through the roof hatch the most precarious movement. This can be overcome by specifying an extension such as the Bilco LadderUp post. This is fitted to the top rungs of a ladder and is operated by the user, sliding it upwards and locking into place with an easy, one handed movement. Equally, when descending, the operative climbs down the first few rungs until the opening is just above their head, then lowers the post before closing the hatch; again, one handed.
The expertise in matching the correct roof hatch to the project still lies mostly with the manufacturer. The wisest move from the specifier, therefore, is to tap into this resource. Bilco certainly encourages this, by making its knowledge available through a number of channels. Recently, Bilco has joined both the National Federation of Roofing Contractors and the Single Ply Roofing Association and is working with both organisations to share technical knowledge in this area.
Bilco is also doing its best to educate the industry by providing CPD seminars at clients’ own premises, helping specifiers to grasp the long term importance of the proficient specification of access products. The Bilco UK website also hosts a wealth of BIM information, NBS Building specifications and full CAD drawings of many of its products.
While there may not be an industry standard for the performance of a roof hatch, at Bilco we’re certainly working hard to establish awareness of what we should all be regarding as the minimum performance of an access hatch.