Facilities systems design and planning is a complex task which requires architects, mechanical engineers, civil engineers, electrical engineers to design these systems. The planning of facility system is typically not the responsibility of the facilities planner. However, the specification of what systems are required where and the integration of the facilities systems into overall facility are generally the responsibility of the facilities planner. The facilities planner must be aware of the following factors:

A facilities planner is not expected to become an architect, mechanical engineer or a structural engineer. However, during the planning stage of a facility, the planner should have a general knowledge about the building technology and the interrelationship of the facility systems, so that the interior handling systems and the layout will not be made without recognizing the reality of the facility constraints. Although there are numerous types of facilities systems, the following are the major groups of facility systems:

The most common structural type for industrial facilities is the steel skeleton frame or reinforced concrete skeleton frame. Many factors will impact the selection of the structural type or materials: for example, fire protection (steel loses its strength when heated above 1000^oF), use environment (steel becomes brittle below -20 ^o F and fails easily), and the overall planning grid or module. The structural design and the grid configuration can have impact on the layout and the layout may impact the interior flow of materials. For example, in a warehouse the column spacing should be dictated by the rack dimensions and the access aisles between racks. The clear spacing between columns must be compatible with the storage system. The facilities planner must recognize that the structural dimensions of the building grid are secondary to the optimal layout of the facility.

A common error in the design of warehousing facilities is the use of building cost criteria to define column spacing and thus determine the grid configuration. The structural members available are usually 20 and 40 ft lengths. Architects and structural engineers often use these lengths in designing a storage system. The structural dimensions of the steel beams and girders or other structural members should be secondary to the storage system for which the facility is intended.

Different pallet sizes affect the dimensions of the racks, and rack dimensions affect the spacing between the columns. Therefore, before designing a building it is important to determine how the facility is to be used. In addition to the rack size, aisle space is also another factor that affects the column spacing. Aisle width is determined by the type of storage and retrieval equipment and vehicles (forklift, etc).

The size and character of the columns must also be considered. Heavy-wall round or square tubular columns should be used in warehouses.

The building's structural integrity is the responsibility of the structural engineer and the architect. The building must exhibit stability under the following load conditions:

The facilities planner must recognize the environmental conditions where facility will be located and the types of load conditions that might render the building unstable.

Enclosure Systems:

The enclosure system provides a barrier against the effects of extreme cold or heat. Lateral forces (wind), water, and undesirable entries (human, insects, chemicals). Doors and windows act as filters to provide not only a barrier but also access to ventilation, light transmission, and sound. The enclosure elements are floor, walls, and roof. These elements are intended to provide the facility with a specified comfort level. This comfort level is often impacted by the thermal performance of the building enclosure.

Typically for manufacturing and warehousing facilities, keeping undesirables out is a key criteria. As such, the material selected should be more impervious to penetration such as metal, plastic or masonry cladding. Thermal performance coupled with water exclusion forms the backbone of most enclosure systems. There are two areas of considerations:

Above ground enclosure systems: The primary performance need of the roof is water exclusion. However, the importance of thermal comfort necessitates the need for adequate insulation. The three factors listed below are essential to an effective roofing system:

A membrane layer to prevent water penetration, an insulation layer to assist with thermal comfort and a vapor check to stop vapor migration are integral elements of the system.

The ground and below ground conditions for industrial facilities is typically a concrete slab which sit directly on the ground. The primary concern with ground conditions are:

The enclosure elements making contact with the ground must be sealed to keep the water out. There are two ways of accomplishing this:

Integral water proofing consists of an additive to the concrete to make it water-tight. This method is not very effective in controlling vapor migration. Typically it can take 12 in. or more of concrete to prevent vapor penetration inwards from the surrounding wet soil.

Membranes can be 100 % effective in handling vapor and water penetration. An effective design method is to apply the membrane on the external surface. This position will allow the membrane to work in conjunction with the hydrostatic pressure of the wet soil surface, and as the hydrostatic pressure increases, the membrane will be pressed more firmly against the structure. This creates a better adherence between the membrane and the building structure than the membranes applied to the internal surfaces.

Atmospheric systems provide for the health and comfort of the building occupants; safe use of the equipment and machinery. The criteria for equipment and machinery is dictated by manufacturer's specification and Occupational Safety and Health standards. Atmospheric systems consist of heating, cooling , ventilation and air conditioning systems (HVAC).

The comfort of the occupants of a facility is affected by the following criteria:

One major problem in most buildings is odor build-up and air borne particulate matter. By definition the rate of dilution is expressed as CFM/ft² which indicates how many ft³ of air is supplied in one minute to 1 ft ² space. The air quality of a space can be improved by:

Indoor air quality can be improved by mixing a portion of the indoor air with fresh outdoor air (dilution). This air exchange (dilution rate) is typically expressed in air changes per hour as stipulated by local code requirements pertaining the use of the building.

In Table 1 typical air change rates are given for various types of buildings.

Table 1. Typical air change rates

Because of the importance of removing odor, chemicals, smoke, fumes, etc, from indoor air, the equipment to remove the indoor air and bring in fresh air is a primary consideration in planning of a facility. The space requirement for HVAC systems is governed by the size of the equipment room, the air speed capabilities of main and branch ducts, and the louver size needed to accommodate the required exhaust and intake air needs.

Equipment Rooms: Central equipment rooms can be estimated from Table 2. As the air change rate requirement increases, the handling equipment area also increases.

Table 2. Central equipment room area by use

Duct size can be estimated from air quantities and air speeds in ducts. Table 3 shows the air speeds.

Table 3. Air speeds in ducts.

 Louver Sizes:

These areas are also estimated from air quantities and air speeds.

Table 4. Air speeds in louvers.

Example: A 200 ft x 100 ft store is to be air conditioned. What would be the space requirements for the HVAC systems ? Assume that the system is roof mounted. Two main ducts and 20 branch ducts (10 branches per main) will be installed.

Figure 1

Total gross area = 200 x 100 = 20,000 ft². From Table 2, using commercial type, assume 5 % of gross area for mechanical equipment space (5 % of 20,000 ft ²) which would be 1,000 ft².

Use maximum air supply rates from Table 1.

Calculate the following:

Calculate the louver cross sections:

Note that supply and exhaust louvers must be at least 15 ft apart to avoid short circuit of exhaust air back into the building.

Two main ducts will be used as shown in Figure 1. Assuming that each main duct will handle 1/2 of the total air requirement (1/2 x 20,000 ft² =10,000 ft² will be covered by each main duct) and 1.0 CFM/ ft² -from Table 1; we can calculate the flow rate in each main duct as follows:

1/2 x 20,000 ft² x 1.0 CFM/ ft² = 10,000 CFM and the cross sectional area of each main duct:

10,000 CFM / 1,800 ft/min = 5.6 ft²

Divide flow rate for each main duct by the number of branches to obtain the branch flow rate.

10,000 CFM / 10 = 1,000 CFM for each branch

From Table 3 select an average speed of (900+1100)/2 =1,000 ft/min. To find the branch duct cross sectional area, divide branch flow rate by the allowable branch duct air speed:

1,000 CFM / 1,000 ft/min = 1 ft²

Summary of the results:

The electrical requirement for a facility is needed by the power company well before construction begins. This usually requires that facilities planners have a good preliminary estimate since the design of the facility is often not finalized when this information is necessary. In general every electrical system should have sufficient capacity to serve the loads for which it is designed, plus spare capacity to meet anticipated growth in the load on the system.

The facilities planner must ensure that major load requirements, both present and future are included in the design data, so that the design engineer can adequately size the mains , switchgear, transformers, panel boards and circuits to effectively handle the growth of the load. The process begins with analyzing the building type and its traditional electrical loads. Table 5 shows the average load requirements for various types of buildings.

Table 5. Average Load Requirements

Life safety systems are designed to control emergency situations that will disrupt normal operations. These emergencies are usually created by:

Fire is the most pervasive of the three and usually accounts the majority of costs. Fire protection in buildings is governed by the Uniform Building Code (UBC). The degree of fire resistance is governed by the type of structure. The Uniform Building Code requires that means of egress be provided in every facility from every part of every floor to a public street or alley. The minimum requirement therefore is at least one exit from every facility and in some cases when the rated number of occupants exceed a certain number two or more exits are needed as stipulated by the building code. In general most buildings require two or more exits. This is done so that other exits are available if one is blocked by fire. In addition, most local building codes will require that maximum allowable time to exit the building not be violated. Also, each exit must be within 150 ft of any point (200 ft for buildings with sprinkler systems), and access must be provided for handicapped persons. It is important to note that the use of elevators are to be avoided during fire. This may entail ramps or an exit passage way for handicapped persons in case of fire.

Table 6 shows the minimum number of exits for occupant load as defined by BOAC (Building Officials and Code Administrators).

Table 6. Minimum Number of Exits for Occupant Load

Sanitation systems consist of hot and cold water supply, a distribution network to supply potable and cleansing water, as well as collection network for refuse. For industrial or plant operations, facilities planner must provide process water and drain requirements to the person planning the plumbing services. In addition, the facilities planner must provide the composition of all process liquids. The treatment or filtering of these liquids must be carefully planned. Plumbing services for fire protection require not only that the proper quantity of water is available but also that the proper water pressure is provided. The most common approach to fire protection is automatic sprinkler systems. The facilities planner 's input into the planning of fire protection plumbing services is a facility layout and a description of the activities to be performed in various areas within the layout.

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Last Update: December 2, 1999

By: Serdar Z. Elgun