Hoists

A construction hoist is a temporary elevator that transports workers and material to the various floors in a building. A hoist car that transports people is classified as an elevator and must conform to a more stringent set of standards then a mere material hoist. The hoist cars typically ride on rails that are tied to the structure every two to three floors. One or two cars ride on one mast. On a dual hoist, one car can be for workers and the other car can be for workers or material. Types of hoists and their car dimensions are indicated in Exhibit 6-11. Photographs of a hoist, hoist supports, and hoist protection are shown in Exhibits 6-12, 6-13, and 6-14. A hoist platform runway is shown in Exhibit 6-15. Hoist runways are required when the hoist is located outboard from the building structure. This would be necessary when there are set backs

Exhibit 6-11

Plan of hoist car.

SCALE: W'VJT

SCALE: W'VJT

LENGTH WIDTH HEIGHT

SQUARE FEET AREA (INSIDE)

LENGTH WIDTH HEIGHT

SQUARE FEET AREA (INSIDE)

US-8002-2R PERSONNEL/MATERIAL HOIST

Exhibit 6-13

Hoist supports.

Exhibit 6-13

Hoist supports.

Exhibit 6-14

Hoist protection.

Exhibit 6-14

Hoist protection.

Exhibit 6-15

Plan of hoist platform runaway.

1. Rack and Pinion Hoists

2. Common Mast

3. Common Platform

4. Runaway to Building

5. Tie Backs and Supports

1. Rack and Pinion Hoists

2. Common Mast

3. Common Platform

4. Runaway to Building

5. Tie Backs and Supports in the building or for ground logistics reasons. In addition, sometimes a common platform is utilized to allow several hoist assemblies to access one large platform structure adjacent to the building, thus allowing for more than two hoists in one location, if required.

The hoist noted can accommodate as many as 40 people and can carry loads of up to 8000 pounds. In a hoist designed for carrying people, the operator typically rides in the car, but in a machine that is not intended for personnel, this is not permitted. The car rides close to the face of the building so that the gap at each landing is small. If the geometry of the installation will not permit this, then a supplemental structure needs to be built to meet the car. A gate only operable from the outside and one on the structure side of the hoist are installed so that each opening is safely closed off. A typical personnel hoist for construction operates at a speed of about 300+ fpm and by certain local codes may not exceed 600 fpm.

Other safety considerations that must be observed include the following:

1. A 30-foot safety area should be maintained around the cars. This will include the installation of safety nets and a sidewalk bridge.

2. A loading dock shed should be constructed that will protect workers and trucks that will be unloading material at the loading dock.

The hoist location within the plan of the structure is determined by several factors:

1. Good access off the street for the unloading of material from trucks.

2. Close to the center of where material will be used on a floor with clear passage that will not interfere with critical finishes.

3. Close to the fire standpipe so that firefighters have ready access when they step off the hoist.

4. Minimal interference with the progress of construction by delaying closing or finishing critical parts of the building.

5. Avoiding potential conflicts with other activities such as crane picks.

6. Access to remove the hoist from the site after the work is completed.

The number of hoists on a project is determined by a cost benefit analysis considering the following:

1. Number of workers that need to go up and down the building at peak times. You want to avoid delays of bringing the workers up to the floors in the morning and then returning during the lunch break. These delays cause losses of productivity.

2. The amount of material that will have to be transported during the progress of the job. In most cases, hoists may be added when the interior work starts for the structure.

3. The cost of renting the hoist and the cost of the operators.

4. Availability of temporary power.

5. The cost benefit of schedule acceleration brought about by more carrying capacity versus the possible delaying effect of leave outs at the hoist locations.

6. A rule of thumb is one hoist car for every 250,000 square feet.

A checklist for hoists is shown in Exhibit 6-16.

Exhibit 6-16

Checklist for hoists.

Item

Included

1. Construction personnel hoists

2. Construction material hoists

3. Combination personnel/material hoists

4. Location of hoist—internal or external to building

5. Loading dock for hoists

6. Barricades for hoists and loading dock

7. Signage

8. Flashing yellow caution lights

9. Concrete foundation pad for hoist

10. Tie backs of hoist to the structure

11. Runaways from hoist tower to building

12. Power for hoists

13. Power for lighting and outlets at hoist landings and loading dock

14. Permits

15. Engineering

16. Sidewalk closing

17. Lane closing

18. Direction of the flow of traffic

19. Bus lanes and stops

20. Subway entrances and exits

21. Access to fire hydrants

22. Visibility of traffic signage or relocation of same

23. Zone of influence of the hoist for sidewalk bridge

24. Sidewalk Bridge for pedestrian protection

25. Lighting under sidewalk bridge

26. Anchorage of sidewalk bridge

27. Weather-resistant enclosure at hoist entrance to building

28. Ramps from hoist entrance into building

29. Coordination of hoist location with permanent building facilities

30. Schedule for the availability of permanent service and passenger elevators

31. Use of hoists for construction of tenant fit up program

32. Structural support for the hoist pad, hoist tiebacks, sidewalk bridge, and sheds

33. Structural reinforcing for the hoist area loading dock

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