UNIT CN1: MANAGING CONSTRUCTION SAFELY 

SCENARIO

The hotel
A busy hotel is located on the edge of a large city. It has three levels and a total of 100 rooms. As the hotel is in high demand, the owner has decided to add 30 new rooms. A Principal Designer (PD) has been both consulted and appointed, and a Principal Contractor (PC) has been hired.
The PD obtains planning permission for a wood frame construction with a brick and decorative panel outer wall. The design for the extension extends the length of the hotel without extending its height. A poured concrete slab base will form the foundation of the extension. The car park and pedestrian areas will remain the same.

The PC appoints contractors to close a section of the footpath and car park with barriers and fencing. There will be a crossing point, which will create an alternative route for pedestrians. The PC also instructs all vehicle drivers to give priority to pedestrians at the crossing point. The Temporary Works Co-ordinator (TWC) is aware of the fencing and scaffolding on the extension, but they are too busy to compile a register of these works
The contractors are allowed to start work before attending the site induction training. However, the PC instructs the contractors to wear their high visibility vest and to put an appropriate sign on the site noticeboard as a reminder for the other workers. They remind the contractors of the site rules and the requirement to wear other personal protective equipment (PPE), including safety glasses and boots. One of the contractors picks up their high visibility vest and safety glasses and walks directly to the car park area.

Laying the foundations
The contracting company, employed to lay the foundations, has arranged for the concrete to be delivered ‘ready mixed’. The TWC issues a permit to fill the formwork, and the concrete is poured. A supervisor, who is employed by the PC and located near the concrete pouring area, hears a crashing sound. As the supervisor approaches, they ask a member of the public to stand clear from the scene. The supervisor investigates further and sees broken parts of the formwork behind the truck’s rear wheels. As the vehicle was reversing, the workers jumped out of the way, but nobody was hurt.

As a result, the supervisor appoints a vehicle marshal. The supervisor arranges a site inspection and a safe place for workers to stand when the concrete pouring is attempted for a second time. To recover some of the lost time on the project schedule, the TWC revises the formwork design. A carpenter is asked to rebuild the re-designed formwork.
A worker is removing air bubbles from the newly-laid concrete using a flexible hose vibrating poker tool (used to consolidate concrete by removing pockets of air). The supervisor is concerned how long this task is taking and asks the worker if the tool is working properly. 

The timber suppliers inform the PC that there is a supply issue and there will be a significant delay in receiving the second batch. The PC is concerned that the project is already behind schedule and the fire door frames still need to be fitted. The PC decides to use readily available untreated timbers.

The incident
Pipework is being installed in the extension by Worker A, who will connect it to the live water mains when the pipework installation is finished. The construction phase plan lists the installation of fire alarms and detection systems before the pipework. Despite this, the supervisor advises Worker A to focus on the water main pipework installation. The supervisor leaves to oversee the delivery of some expensive acoustic panels. For security, they agree to store the panels in a corridor of the new construction.
Worker A begins using a plumber’s blow torch to heat one of the pipes. They place the lit blow torch upright on the floorboard, near their foot, while the pipe cools. Meanwhile, directly below Worker A, Worker B is using a nail gun to fix ceiling joists together.

A nail pierces the floorboards near where Worker A is standing. They are startled and react by jumping backwards without looking. They are unaware that they have caused the blow torch to fall over. Worker A goes to find Worker B on the lower level. They find them standing by a warning sign advising the area has nail guns in use. Worker A tells them what happened and asks them to be more careful. Worker B apologises, saying that the depth gauge dial for the nails was correctly set on the nail gun. While trying to reach the correct section of timber, they had lost balance and accidently fired the nail into a thinner section of timber. The nail gun was dropped, and the casing was damaged while Worker B tried to regain their balance. Worker B shows Worker A the damaged nail gun; Worker A also observes a heat haze coming from the fractured casing.

Meeting with the Temporary Work Co-ordinator (TWC)
The HSA meets the TWC to discuss the damaged formwork on the concrete floor slab. The TWC has recently completed an approved training course and they produce the risk assessment for the concrete floor slab. The risk assessment shows control measures were considered for the reversing concrete pouring truck. The temporary works procedures were checked and are up-to-date. They include an authorisation page with the PC’s signature on it.

When the original design brief for pouring the concrete had been submitted, the client encouraged the use of a ‘chute’ vehicle, rather than boom pump, to keep costs down. The TWC said they had checked the formwork design and had made a change to allow the vehicle to get closer to use the chute. A change from the design drawings was needed to allow the concrete pour to take place. They also communicated health and safety information to the floor slab team.
On closer examination of the procedures that the TWC had created, factual inaccuracies and repetition of phrases and words were found in the document.