HOW TO SELECT A FLOOR DRAIN
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Floor drains are primarily used for inside locations where the flow rate into the drain can be anticipated and for outside areas where rainfall intensity dictates sizing. Drains should be selected with sufficient top size and grate free area to pass the anticipated flow. Grate free area is defined as "the total area of the drainage openings in the grate." The drain outlet should be sized large enough so that it will safely pass the maximum flow through the grate, without creating water buildup.

Sizing and Location– For most indoor locations, the grate free area should be 1 1/2 times the transverse area of the connecting pipe. The number and location of drains are based on the configuration of the floor plan, type of operation and location of equipment. Location and number of floor drains required can be determined only after careful review of the plans and anticipated building use.
Floor drains or area drains, when used to drain exterior areas, should have an open area equal to twice the transverse area of the connecting pipe (Table 1). See roof drain section for rainfall and sizing data.

SELECTING THE DRAIN

After the top size is determined based on anticipated flow into the drain, the following points should be considered when making the final selection of the floor drain.

Selection of Top (Based on Anticipated Traffic)– Establish the maximum anticipated traffic (loading) which will pass over the grate and select the grate type which will support that load. Each drain shown in this section has a description listing the type of load it will take. The categories listed are for various drains in respect to grate loading. The load classifications are in accordance with the American National Standards ASME A112.21.1M. ASME Ratings are as follows:

• Light Duty– All grates having safe live load under 2,000 lbs. (900 KG)
• Medium Duty– All grates having safe live load between 2,000 lbs. (900 KG) and 4,999 lbs. (2250 KG)
• Heavy Duty– All grates having safe live load between 5,000 lbs. (2250 KG) and 7,499 lbs. (3375 KG)
• Extra Heavy Duty– All grates having safe live load between 7,500 lbs. (3375 KG) and 10,000 lbs. (4500 KG)

The above categories are given as a guide only. Conditions of use, load concentrations, installations, etc., can affect results and service. For unusual applications, consult our Sales Engineering Department.

After the weight loading capacity is established, a suitable drain can be selected.

Illustrated below are various types of grate designs which will be mentioned throughout the catalog.

 

Selection of Top Material– (Unfinished Areas)–Drains located in heavy traffic areas should be specified with heavy duty cast iron grates. In areas where shock loads are anticipated, a ductile iron grate should be specified in lieu of the cast iron grate. Cast iron is acceptable for most unfinished areas such as warehouses, loading docks, boiler rooms and similar areas.

(Finished Areas)– Most drains are available with nickel bronze or bronze tops to match the surrounding trim in finished areas. Usually finished areas require light duty or medium duty tops.

(Finished Areas with Increased Load)– Many finished floor areas are subject to increased loadings. Examples are convention centers, equipment showrooms and industrial plants. Heavy duty cast iron tractor grates can be specified with bronze or nickel bronze veneered tops. (Specify Fig. No. 2120, 2140, 2250, etc.)

Top Shape– Round, square or rectangular styles are available to blend with all types of construction and floor patterns. The round top is the most flexible type since it can be easily oriented to most floor patterns.

Body Selection– Body depth is proportioned to the top size. Many Smith floor drains can be specified with various body depths. The deeper body is desirable when unusually large amounts of water are to be drained or an extra large sediment bucket is required.
 

Most floor drain bodies are available with a flange for either anchoring the drain in the floor slab or for use as a flashing flange in upper floors and waterproofed areas. Many Smith drains are regularly furnished with a flanged body and a combination "top flashing collar" which can be used to clamp the waterproof membrane.

PREFIX DX-WIDE FLANGE BODY DRAINS

The Prefix DX designates a wide flange that can be furnished on certain Smith floor drains. This flange receives the membranes and coatings of a waterproof floor covering system. These coverings are thin coatings which are installed in a series of trowel coats. The covering forms its own membrane, flashing and durable traffic surface. The wide flange is regularly furnished 4" wide. The usual covering is approximately 3/16" thick and may be applied over many subsurfaces such as concrete, gypsum or wood decks. This type of covering is particularly adaptable to flat roofs which are used for recreational purposes, balconies, area ways, plazas, sun decks, floors and corridors.

When a DX flange is required on drains other than those shown in this section, the prefix DX must be used with the figure number. The flange will be 4" wide (minimum) with a 3/16" lip regularly furnished. If the waterproof deck covering is greater or less than 3/16", the lip dimension must be specified or the drain has to be set at the proper elevation by the plumbing contractor to compensate for these differences. Roughing dimensions of the body must be adjusted accordingly. Drain body should be set low enough to permit "dimpling" of the area surrounding the drain.

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