A sprinkler pipe schedule chart in NFPA 13 is a table that sets the maximum number of sprinklers each pipe size may supply, and it is used only by the pipe schedule method under specific conditions. Sprinkler spacing comes from the protection area tables in Chapter 10, and the flow from each head is calculated with Q = K√P, using the K-factor from the data sheet and the pressure at the sprinkler.
This is a quick reference for engineers: where each table sits in the standard, how to read it, and which values we verified, with the edition and section. Where we could not find an accessible authoritative source, we explain the method instead of printing numbers, because copying a table from an unverified version is worse than not copying it. AZEIDK designs, supplies and installs sprinkler networks as part of its fire fighting systems in Saudi Arabia, and prepares layouts and calculations through its engineering design and calculations service.
Key takeaways
- NFPA 13 pipe schedules sit in Section 28.5 (2022 numbering). The method is permitted for new systems up to 5,000 ft² (465 m²), or larger where the required flow is available at a 50 psi residual pressure at the highest sprinkler.
- Maximum distance between standard sprinklers is 15 ft (4.6 m) for light and ordinary hazard and 12 ft (3.7 m) for extra hazard in the general case; distance to a wall may not exceed half the maximum spacing.
- For ordinary hazard, a standard spray sprinkler may protect no more than 130 ft² (about 12 m²) under Table 10.2.4.2.1(b) of the 2025 edition.
- Head flow is Q = K√P: a K5.6 sprinkler at 10 psi gives about 17.7 gpm, and a K8.0 sprinkler at the same pressure about 25.3 gpm.
- Extended coverage, sidewall and storage sprinklers are designed from the manufacturer’s tables in the data sheet, not from the general tables.
In this article
- Sprinkler Pipe Schedule Chart: What Does It Mean?
- Sprinkler Distance: How to Read the Protection Area Tables
- Fire Sprinkler Head GPM Chart: Q = K√P
- Density or Minimum Pressure: Which Sets the Head Flow?
- Manufacturer Tables: the TYCO EC-8C Corridor Sprinkler
- When Do You Move from Tables to Hydraulic Calculations?
- What Does the Consultant Check on Sprinkler Drawings?
- Frequently Asked Questions
- Summary
Sprinkler Pipe Schedule Chart: What Does It Mean?
On site, “pipe schedule” is used in two different senses, and it helps to separate them before any discussion with the consultant:
- The NFPA 13 sizing table: it links pipe size to the maximum number of sprinklers it may supply, by hazard classification and pipe material (steel or copper). This section is about that table.
- Pipe wall thickness (Schedule 10 or Schedule 40): a property of the pipe specification itself, covered with pipe types and grooved joints in Fire Pipes: Types, Schedules and Grooved Joints.
When is the pipe schedule method permitted?
The 2022 text of Section 19.2.2, as shown in the First Draft Report of the 2025 revision cycle published by NFPA (revision FR-1275), permits the pipe schedule method for new systems in two cases: a system of 5,000 ft² (465 m²) or less, or a larger system where the flows required in Table 19.2.2.1 are available at a minimum residual pressure of 50 psi (3.4 bar) at the highest elevation of sprinkler. The committee statement in the same revision says the provisions for existing systems were moved out of this location, so for an addition or modification to an older pipe schedule system, go back to the edition adopted for the project.
How to read the table
- Fix the hazard classification first, because each class has its own table. See Sprinkler Hazard Classification Under NFPA 13.
- Pick the material column: steel or copper, each has its own column.
- Start at the end of the branch line and count the sprinklers each pipe segment supplies.
- Select the smallest size whose limit covers that count, then move to the next segment back to the main.
We deliberately do not print the table values here: we found no accessible official NFPA copy showing the full table, and the numbers circulating online rarely state the edition or separate steel from copper. Take the values directly from the edition adopted for the project.
Sprinkler Distance: How to Read the Protection Area Tables
The protection area tables for standard spray sprinklers in NFPA 13 are Table 10.2.4.2.1(a) for light hazard, (b) for ordinary hazard and (c) for extra hazard. Each gives two limits: maximum protection area per sprinkler and maximum distance between sprinklers. Values change with ceiling construction type and design method, which is why the Los Angeles Department of Building and Safety (LADBS) checklist for the 2025 edition asks for the ceiling construction type on the plans.
The area of coverage per sprinkler follows the S × L rule: S is the distance along the branch line, L the distance between branch lines, and at a wall each is taken as twice the distance to the wall. Both are measured to the sprinklers, not to the pipe centerlines.
| Item | Value | Reference |
|---|---|---|
| Maximum distance between sprinklers, light and ordinary hazard | 15 ft (4.6 m) | NFPA 13-2025, Tables 10.2.4.2.1(a) and (b) (LADBS) |
| Maximum distance between sprinklers, extra hazard | 12 ft (3.7 m) in the general case; the table sets the cases by density and design method | NFPA 13-2019, Table 10.2.4.2.1(c) (NFSA presentation) |
| Maximum protection area, ordinary hazard | 130 ft² (about 12 m²) | NFPA 13-2025, Table 10.2.4.2.1(b) (LADBS) |
| Maximum protection area, light hazard | Varies with ceiling construction | NFPA 13-2025, Table 10.2.4.2.1(a) |
| Distance from wall | Not more than half the maximum spacing, and not less than 4 in. (about 10 cm) unless listed for closer | NFPA 13-2019, Section 10.2 (NFSA presentation) |
| Minimum distance between sprinklers | Sprinklers closer than 6 ft (1.8 m) must be separated by baffles | NFPA 13-2025, Section 10.2.6.4.2 (LADBS) |
| Deflector below ceiling | Not more than 12 in. (about 30 cm) in the general case | NFPA 13-2025, Section 10.2.7.1.1.1 (LADBS) |
Example: in ordinary hazard, sprinklers at 12 × 10 ft protect 120 ft² each, within the 130 ft² limit. At 12 × 12 ft they protect 144 ft² and exceed it even though each distance is below 15 ft, so both limits are checked together. For deflector position by orientation, see Upright vs Pendent Sprinkler.
Sidewall and extended coverage sprinklers
Sidewall sprinklers have shorter spacing limits than standard upright or pendent sprinklers, and extended coverage sprinklers are not laid out with the standard sprinkler tables but with the area, flow and pressure listed in the data sheet for each model. Details are in Sidewall Sprinklers.
Fire Sprinkler Head GPM Chart: Q = K√P
The flow from any sprinkler equals its discharge coefficient K multiplied by the square root of the pressure at the sprinkler: Q = K√P, with Q in gpm and P in psi. In metric units the metric K is used with pressure in bar to give flow in L/min. K is never assumed; it comes from the data sheet. TYCO technical data sheet TFP151 for Series TY-B, for example, gives K5.6 (80.6 L/min/bar½) for models TY3151 and TY3251, and K8.0 (115.2) for TY4151 and TY4251.
The table below is calculated directly from the formula with those K-factors:
| Pressure at sprinkler (psi) | K5.6 flow (gpm) | K8.0 flow (gpm) |
|---|---|---|
| 10 | 17.7 | 25.3 |
| 15 | 21.7 | 31.0 |
| 20 | 25.0 | 35.8 |
| 30 | 30.7 | 43.8 |
| 50 | 39.6 | 56.6 |
In metric terms, a K80.6 sprinkler at 1 bar delivers 80.6 L/min and at 2 bar about 114 L/min. Doubling the pressure does not double the flow; it raises it by only about 41%.
Pressure limits
- Minimum: NFPA 13 sets a minimum sprinkler operating pressure within its hydraulic calculation rules, and manufacturers set a minimum pressure in the data sheet for certain models, such as the extended coverage sprinklers below. Take both from the text of the edition adopted for the project and from the data sheet; the higher value governs.
- Maximum: the maximum working pressure of most TY-B models is 175 psi (12.1 bar) per TFP151, and the LADBS checklist requires listed pressure reducing valves where pressure exceeds 175 psi, citing Section 16.9.7.1 of the 2025 edition.
For K-factor, temperature ratings and response types, see Sprinkler Head Types: K-Factor, Temperature Rating and Response.
Density or Minimum Pressure: Which Sets the Head Flow?
In the density/area method each sprinkler must discharge at least the design density times its protection area, and at least its flow at the minimum pressure. The larger of the two goes into the calculation. Example for Ordinary Hazard Group 1, with a density of 0.15 gpm/ft² from Table 19.2.3.1.1 (NFPA errata for the 2022 edition) and a 130 ft² protection area:
| Step | K5.6 sprinkler | K8.0 sprinkler |
|---|---|---|
| Flow required by density: 0.15 × 130 | 19.5 gpm | 19.5 gpm |
| Pressure needed: P = (Q/K)² | about 12.1 psi | about 5.9 psi |
| Check against minimum pressure | Compare 12.1 psi with the minimum in the adopted edition and the data sheet | Compare 5.9 psi with the same minimum |
| Design flow per sprinkler | 19.5 gpm at 12.1 psi unless the minimum is higher | If the minimum Pmin is above 5.9 psi, pressure is raised to it and flow becomes 8.0 × √Pmin, more than 19.5 gpm |
The larger orifice needs less pressure, but once raised to the minimum pressure it discharges more than the density requires, which adds to the total demand when several sprinklers are in the design area.
Manufacturer Tables: the TYCO EC-8C Corridor Sprinkler
For extended coverage sprinklers the manufacturer publishes a ready table of area, flow and pressure. The Johnson Controls corridor sprinkler family flyer (FS2105015) gives the following for the TYCO EC-8C TY4282 light hazard, quick response recessed pendent sprinkler, with the RFII-C concealed sprinkler for comparison:
| Model | K | Coverage | Minimum flow | Minimum pressure |
|---|---|---|---|---|
| EC-8C (TY4282) | 8.0 | 28 × 8 ft (8.5 × 2.4 m) | 23 gpm (87.1 L/min) | 8.3 psi (0.6 bar) |
| EC-8C (TY4282) | 8.0 | 28 × 10 ft (8.5 × 3.1 m) | 28 gpm (106 L/min) | 12.3 psi (0.9 bar) |
| RFII-C (TY3582) | 5.6 | 28 × 8 ft | 23 gpm | 16.9 psi (1.2 bar) |
| RFII-C (TY3582) | 5.6 | 28 × 10 ft | 28 gpm | 25 psi (1.7 bar) |
The required flow is the same for the same coverage; only the pressure changes with K, exactly as the formula predicts: 8.0 × √8.3 ≈ 23 and 5.6 × √16.9 ≈ 23. The AZEIDK product page notes that smaller or in-between coverage areas use the flow of the next larger listed area. Always check the full data sheet for the model before approving the design.
When Do You Move from Tables to Hydraulic Calculations?
- When the pipe schedule conditions above are not met, which is the case for most medium and large projects.
- At higher densities: the LADBS checklist cites Sections 21.1.3 and 21.1.4 of the 2025 edition requiring standard response sprinklers of K8.0 or larger for densities above 0.20 up to 0.34 gpm/ft², and K11.2 or larger above 0.34.
- With ESFR and control mode storage sprinklers, whose design depends on storage and ceiling height and the data sheet values, as covered in Fire Protection for Warehouses and Logistics Facilities.
A hydraulic calculation starts at the most remote sprinkler with Q = K√P, then adds pipe friction loss using the Hazen-Williams formula back to the water supply. The review steps are explained in Sprinkler Hydraulic Calculations, and the scope of the standard in NFPA 13: Standard for Sprinkler System Design and Installation.
What Does the Consultant Check on Sprinkler Drawings?
- The NFPA 13 edition adopted for the project, because table values and section numbers change between editions.
- The hazard classification of each area, and the ceiling construction type behind the protection area used.
- S and L dimensions and wall distances for every room, not only a typical one.
- Sprinkler model, K-factor and minimum pressure from the data sheet, with the SIN.
- The sizing method: pipe schedule with evidence that its conditions are met, or a full hydraulic calculation.
- Maximum pressure at the lowest point, and pressure reducing valves where needed.
Frequently Asked Questions
What is a sprinkler pipe schedule chart?
A table in NFPA 13 that sets the maximum number of sprinklers each pipe size may supply, by hazard classification and pipe material. It is used by the pipe schedule method instead of hydraulic calculation, under specific conditions.
What is the maximum distance between fire sprinklers?
For standard spray sprinklers, 15 ft (4.6 m) in light and ordinary hazard and 12 ft (3.7 m) in extra hazard in the general case, while also respecting the maximum protection area in each hazard table.
How far should a sprinkler be from a wall?
Not more than half the maximum allowed spacing between sprinklers, and not less than 4 in. (about 10 cm) unless the sprinkler is listed for a closer distance.
How many gpm does a fire sprinkler head flow?
It depends on K and pressure: Q = K√P. A K5.6 sprinkler at 10 psi flows about 17.7 gpm, and at 20 psi about 25 gpm.
Can a pipe schedule replace hydraulic calculations?
Only for new systems up to 5,000 ft², or larger ones where the required flow is available at 50 psi residual at the highest sprinkler, per the 2022 text. Otherwise a hydraulic calculation is required.
What is the difference between Schedule 40 and the NFPA 13 pipe schedule?
Schedule 40 is the pipe wall thickness in its specification, while the NFPA 13 pipe schedule is a method for sizing pipe by the number of sprinklers. One is a product property, the other a design method.
Summary
NFPA 13 design tables work together: protection area tables set how many sprinklers you need and where, Q = K√P with the data sheet sets the flow from each head, and the pipe schedule or a hydraulic calculation sets the pipe sizes. The constant rule is to take every number from the edition adopted for the project or from the manufacturer’s sheet for the exact model.
Have architectural drawings and need a sprinkler layout and pipe sizing? Send the drawings, occupancy and ceiling heights, and the AZEIDK team will prepare the layout, calculations and bill of quantities. Contact AZEIDK
