EFFECTIVE DATE: 06/20/2011 EXPIRATION DATE: 03/31/2013 

 (Reissue of P08-V-5) 

PROGRAM POLICY LETTER NO. P11-V-15 

FROM: KEVIN G. STRICKLIN

 Administrator for 

 Coal Mine Safety and Health 

 LINDA F. ZEILER

 Acting Director of Technical Support 

SUBJECT: Interpretation of 30 C.F.R. 75.1100-1 and 2 Regarding Water 

 Delivery Capability of Coal Mine Waterlines when Fighting a Fire 

 with a Firehose and Nozzle 

Scope

This Program Policy Letter (PPL) applies to all miners, miners’ representatives, Coal 

Mine Safety and Health (CMS&H) enforcement personnel, and underground coal mine 

operators. 

Purpose

This PPL clarifies the performance test requirements used by the Mine Safety and 

Health Administration (MSHA) for determining compliance with Title 30 Code of 

Federal Regulations (30 C.F.R.) §75.1100-1(a) concerning the water delivery capability of 

waterlines used for fighting a fire with a firehose and attached nozzle. This PPL also 

clarifies the intent of the MSHA Program Policy Manual (PPM), Volume V, Section 

75.1100-1 regarding this standard. The PPL is intended to answer questions, eliminate 

inconsistencies, and provide guidance to enforcement personnel and the mining 

industry. MSHA will be re-evaluating waterlines used for fighting a fire with a fire 

hose to assure that adequate fire protection is afforded under the standard. 

Policy

The standards contained in §75.1100 are derived from the statutory provisions in 

Section 311(a) of the Federal Mine Safety and Health Act of 1977. The statutory 

provision states that: “Each coal mine shall be provided with suitable firefighting 
2

equipment adapted for the size and conditions of the mine. The Secretary shall 

establish minimum requirements for the type, quality, and quantity of such 

equipment.” 

Standard 75.1100-1(a) requires that: “Waterlines shall be capable of delivering 50 

gallons of water a minute at a nozzle pressure of 50 pounds per square inch.” This is a 

minimum performance standard and is commonly referred to as the “50/50” rule. 

The current PPM policy addressing §75.1100-1(a) states that: “Waterlines, with hoses 

attached, shall be of sufficient size to deliver 50 gallons of water per minute at a nozzle 

pressure of 50 psig.” (psig means pounds per square inch gage) Although the current 

policy indicates that hose is to be included in the performance evaluation, it does not 

define the length, size (diameter), or type of hose to be considered. This PPL revises the 

policy to state that the length of hose used for determining compliance depends upon 

the location in the mine, which will fall into two categories: the “the working section of 

the mine” and “all other areas of the mine.” 

The length, size, and type of hose affect compliance with the performance standard 

because water flowing through a hose will create pressure loss along the hose due to 

friction. The magnitude of this friction pressure loss will depend upon the water flow 

rate and the length, size, and type of hose. 

To compensate for pressure friction loss, the available pressure in the waterline at each 

valved firehose outlet (VFO) must be equal to or greater than the required nozzle 

pressure plus the expected friction pressure loss. The valved firehose outlet is the point 

where the firehose is connected to the waterline and is also commonly referred to as a 

firehose outlet, hose tap, fire tap, fire valve, outlet valve, or fire hydrant. For the intent and 

purpose of the fire protection regulations for underground coal mines (30 CFR, Part 75, 

Subpart L) all of these terms are synonymous. However, this list is not intended to be 

all inclusive as some mines may have additional terms for this equipment. 

Consideration must also be given to increases in elevation between the VFO and the fire 

hose nozzle. For each twelve (12) feet of increase in elevation, an additional five (5) psi 

should be available at the VFO to compensate for the change in elevation. Where 

elevation changes may be a concern, mine operators should contact their local MSHA 

field office or the MSHA district office for guidance. MSHA personnel can contact 

Technical Support for assistance in evaluating the need for elevation pressure 

adjustments. 

Detailed information on calculating friction pressure losses in various hose 

arrangements, and in making adjustments for elevation, can be found in Appendix A of 

this PPL. 
3

The Working Section of the Mine

For the working section of the mine, the length and size of hose used for determining 

compliance with the 50/50 rule shall be the length and size of the continuous miner 

water supply hose if this hose is also intended for use as a fire fighting hose. 

As an example, consider 700 feet of 1.25 inch diameter continuous miner hose also 

intended to be used for fighting a fire at the face area with negligible elevation change. 

The calculated friction pressure loss in the hose when flowing 50 gpm is 140 psi. In 

order to provide 50 psig at the nozzle, the waterline pressure at the VFO must be 190 

psig when flowing the required 50 gpm. 

When miner hose is also intended for fire fighting, a nozzle must be stored at a readily 

accessible strategic location and any adapters needed to connect the nozzle to the miner 

hose should be stored with the nozzle. 

For fighting purposes on the section, MSHA prefers the use of dedicated firehose over 

the use of the continuous miner hose. When such firehose is provided on the section, its 

size shall be used for determining compliance. The length of firehose stored shall be at 

least the same length as that of the continuous miner hose. Continuous miner hoses 

often exceed 500 feet in length. The 700 feet of 1.25 inch hose in the cited example above 

represents a typical continuous miner hose arrangement. 

Additional technical considerations in using miner hoses for fighting a fire on the 

working section are discussed in Appendix B. 

All Other Areas of the Mine

For all other areas of the mine, the length and size of firehose considered in the 

compliance determination shall be 500 feet of the size and type of firehose being stored 

along the belt conveyor line. 

For belt conveyors, §75.1100-2(b) requires a minimum of 500 feet of firehose to be stored 

at a strategic location along each belt flight. To effectively utilize this hose, valved 

firehose outlets connected to the waterline must be provided at a spacing of no greater 

than every 300 feet along the belt entry. 

Furthermore, §75.1100-2(c) requires that each haulage track entry must also have valved 

firehose outlets spaced no greater than every 500 feet apart. When the haulage track 

entry is adjacent to the belt entry, the belt entry hose outlets can often fulfill the track 

entry hose outlet requirement as long as the maximum travel distances between hose 

outlets is not exceeded for either entry. Operators should contact their local MSHA 

field or district offices for additional guidance on this issue. 

In order to fight a fire in areas other than the working section, it may be necessary to 

connect the full 500 feet of firehose stored at one location into a single hose lay with 
4

attached nozzle. Therefore, MSHA requires that 500 feet of firehose be included when 

evaluating the compliance of the waterline with the performance standard. 

As another example, consider 500 feet of 1.5 inch diameter firehose with negligible 

elevation change. The calculated friction pressure loss when flowing 50 gpm is 30 psi. 

Therefore, in order to provide 50 psig at the nozzle, the waterline pressure at the VFO 

must be 80 psig when flowing the required 50 gpm. 

Additional important information on issues involving firehose sizes, lengths, and types 

can be found in Appendix B. Appendix B also includes several examples of compliance 

determination. 

Water Flow Measurements

The PPM for §75.1100-1 states that, “Water flow through the nozzle can be measured by 

a pitot tube instrument if the diameter of the nozzle orifice is known.” The revised 

policy now includes additional recognized test methods and devices, such as in-line 

flow meters and pressure gages in conjunction with known orifices, as acceptable for 

determining compliance with the performance standard. Appendix C describes an 

example of one test device that may be used by MSHA compliance officers and 

technical support personnel. 

Background

Questions have been raised concerning the important need for testing and evaluating 

the capability of mine water systems to supply adequate water for fire fighting 

purposes in light of the number of recent belt conveyor fires. 

The performance standard in §75.1100-1(a) requires that waterlines be capable of 

delivering 50 gpm at a nozzle pressure of 50 psig. Neither the performance standard 

nor the Program Policy Manual provides details on how to determine compliance with 

this rule. Of particular concern has been the use of undersized waterlines in some coal 

mines (typically three-inch diameter and smaller pipes, but in some cases also four-inch 

lines). While small waterlines may be capable of providing sufficient water for dust 

control during mining operations, these smaller lines typically create excessive pressure 

losses at water flow rates adequate for fighting a mine fire. The use of either small 

waterlines or small firehoses, or both, increases the difficulty of complying with the 

50/50 rule. 

It is important to note that compliance with the 50/50 rule does not waive compliance 

requirements with other fire protection water supply performance standards. These 

include the requirements established for deluge-type water spray systems (§75.1101-

1(b)), and water sprinklers systems (§75.1101-8(c)) used to protect belt conveyor drives. 

It also includes requirements for sprinkler or water spray systems used to protect 

electrical equipment containing hydraulic fluids (§75.1107-1). Determination of 
5

compliance with these other fire protection water requirements may require additional 

considerations, methods, equipment, and/or analysis. 

Authority

The Federal Mine Safety and Health Act of 1977, and 30 C.F.R. §§ 75.1100-1(a), 75.1100-

2(b), and 75.1100-2(c). 

Filing Instructions

This policy letter should be filed behind the tab marked “Program Policy Letters” at the 

back of Volume V of the Program Policy Manual. 

Internet Availability

This policy letter may be viewed on the Internet by accessing the MSHA Home Page 

(http://www.msha.gov) and then choosing “Compliance Info” and “Program Policy 

Letters.” 

Issuing Office and Contact Persons

Coal Mine Safety and Health, Safety Division 

Stephen J. Gigliotti, (202) 693-9479 

E-mail: gigliotti.stephen@dol.gov

Michael Kalich, (202) 693-9714 

E-mail: Kalich.michael@dol.gov

Technical Support – Approval & Certification Center 

Derrick M. Tjernlund, (304) 547-2301 

E-mail: tjernlund.derrick@dol.gov

Michael Hockenberry, (304) 547-2075 

E-mail: hockenberry.michael@dol.gov

Distribution

Underground Coal Mine Operators 

Miners’ Representatives 

Independent Contractors 

Mining Product Manufacturers 

Special Interest Groups 

Coal and All-Volume Program Policy Manual Holders 
6

PROGRAM POLICY LETTER NO. P11-V-15 – APPENDIX A 

SUBJECT: Interpretation of 30 C.F.R. 75.1100-1 and 2 Regarding Water Delivery 

Capability of Coal Mine Waterlines When Fighting a Fire with a Firehose 

and Nozzle 

Firehose Friction Loss and Elevation Pressure Calculation Methodologies

Fire Hose Friction Loss

The standard formula for calculating pressure friction losses in firehose is: 

lcqFL

2 

Where 

FL = friction pressure loss in pounds per square inch. 

c = constant of proportionality that changes for different hose 

 diameters and types. 

q = water flow rate through the hose in gallons per minute divided by 100 

l = hose length in feet divided by 100 

Typical values of c for commonly used rubber-lined hoses are as follows: 

Hose diameter c value

 1 150 

 1-1/4 80 

 1-1/2 24 

 1-3/4 15.5 

 2 8 

The above equation, along with values of c for various hoses, can be found in the Fire 

Protection Handbook published by the National Fire Protection Association (NFPA). 

Note that the two smallest hose sizes listed above are not normally associated with 

firehose. 

 

EXAMPLE CALCULATION 

Calculate the friction loss in 500 feet of 1-1/2 inch hose flowing 50 gpm. 

From the chart above, c = 24 for 1-1/2 inch hose. 

q = 50gpm÷100 = 0.5 

l = 500feet÷100 = 5 
7

         30525.02455.024 2 2 lcqFL    psi 

The total required pressure at the hose outlet then becomes: 

30psi + 50psig = 80 psig. 

As indicated under the Background heading of this PPL, the 1-inch and 1-1/4-inch 

hoses above are not normally available firehose sizes. These hose sizes would typically 

be represented by the rubber-lined pressure hoses used to supply a continuous miner 

with dust suppression water. These small hose sizes typically create excessive friction 

loss and reduce the likelihood of compliance with the 50/50 rule. Also note that the full 

length of the miner hose must be accounted for in the friction loss calculation, especially 

since it is not unusual for these hoses to exceed 500 feet in length. 

The c values for other firehose sizes can be found in the referenced NFPA Fire 

Protection Handbook. However, as an alternative source for this data, the mine 

operator can contact the hose manufacturer directly. 

Using the NFPA methodology and c values, the needed pressures at the hose outlet for 

various hose sizes and lengths, with 50 gpm flowing, are: 

Table of hose friction losses and pressure requirements

hose 

diameter 

(inches) 

hose 

length 

(feet) 

friction 

loss in hose 

(psi) 

total pressure 

required at 

hose outlet 1

(psig) 

1 500 188 238 

1 700 263 313 

1.25 500 100 150 

1.25 700 140 190 

1.5 500 30 80 

1.5 700 42 92 

1.75 500 19 69 

1.75 700 27 77 

2 500 10 60 

2 700 14 64 

 

1

 Friction loss plus 50 psi nozzle pressure 
8

Note that 700 feet represents the length of a typical continuous miner hose. If a mine is 

using a different length miner hose, the methods provided in this appendix can be used 

to determine the friction pressure loss and the pressure required at the hose outlet. 

It is also very important to note that the presence of water pumps in the water system, 

including underground water pumps, adds additional issues of complexity in 

evaluating both the capacity and reliability of the water supply for firefighting. MSHA 

Technical Support should be contacted where concerns exist for these issues. 

Changes in Elevation

Most coal mines are relatively level. However, some mines can have a noticeable change 

in elevation within the length of a lay of fire hose or miner hose. Generally, changes in 

elevation over this distance exceeding about ten (10) feet should be included in the 

analysis. Since uphill directions from the VFO represent the worst case situation, only 

uphill changes in elevation should be included in the analysis. 

For each vertical change in elevation of one foot, an additional pressure of 0.434 psi 

must be added to the pressure requirement at the VFO. This works out to 

approximately 5 psi for each twelve feet of elevation increase. 

REVISED EXAMPLE CALCULATION 

Using the previous example, assume that the belt entry is on a ten percent slope. For a 

500 foot hose lay, this would represent an elevation change of approximately 50 feet 

from the VFO to the nozzle. The elevation pressure can be found by multiplying the 

elevation change by 0.434, or by dividing the elevation change by 12 and then 

multiplying by 5. 

First method

elevation pressure = 0.434 ×50 = 22 psi 

Second method

elevation pressure 215 psi 12

50



Either value can be rounded down to 20 psi since pressure gages are generally read to 

the nearest 5 psi value. 

The total required pressure is now the sum or the nozzle pressure, friction loss, and 

elevation pressure or: 

50psi + 30psi + 20psi = 100 psig. 

Hence, the FVO must be capable flowing 50 gpm at a pressure of 100 psi. 
9

PROGRAM POLICY LETTER NO. P11-V-15 – APPENDIX B 

SUBJECT: Interpretation of 30 C.F.R. 75.1100-1 and 2 Regarding Water Delivery 

Capability of Coal Mine Waterlines When Fighting a Fire with a Firehose 

and Nozzle 

Technical Issues Involving Mine Water Supplies Used for Fire Fighting and 

Compliance Assistance Examples

GENERIC ISSUES ON PERFORMANCE CAPABILITY 

In order to fight a fire using a hose line and nozzle, an adequate rate of water flow, 

along with sufficient pressure, must be available at the nozzle. Sufficient flow rate must 

be available to effectively cool and quench the heat generated by the burning material. 

This material can typically include coal, conveyor belting, hydraulic fluids and greases, 

paper and cardboard packaging for mining supplies, and wood cribbing. 

Sufficient pressure must be available to ensure that the water flow pattern from the 

nozzle has the proper shape and reach. Effective nozzle pattern shape helps ensure 

efficient use of the water being applied to burning surfaces. Effective reach helps ensure 

that those fighting the fire can maintain a safe distance from the effects of the fire 

during firefighting operations. Fires in underground coal mines not only produce 

deadly smoke and heat, they can also cause dangerous roof conditions in close 

proximity to the fire. Therefore, being able to fight the fire from a distance is a crucial 

safety issue. 

HOSE DIAMETER ISSUES 

The most common firehose used for manual firefighting has a diameter of one-and-onehalf inches (a.k.a. 1-1/2 or 1.5). This size of hose is reasonably easy to handle while still 

delivering flow rates capable of suppressing many fires. Larger diameter firehoses are 

also available and have the benefit of yielding lower friction losses or higher water flow 

rates, which ever is deemed more beneficial by the mine operator. However, larger 

firehoses also have the disadvantages of being heavier, thus requiring greater 

manpower, effort, and time to layout during a fire or clean and return to service after a 

fire. These hoses also have a higher initial cost and can require additional training. 

The only official firehose smaller than 1.5 inch is one-inch diameter hose. It is intended 

only for wild land firefighting and is often referred to as “forestry hose.” It is not

suitable for fighting fires in mines or structures since it generally cannot deliver the 

flow and nozzle pressure needed to meet the performance standard. 

CONTINUOUS MINER HOSE ISSUES 

For dealing with fires at the working section and face, many mines have made plans for 

using the rubber hose supplying water to the continuous miner as the hose for fighting 
10

a working section fire. For modern continuous miners, this hose is typically 1-1/4 

inches in diameter, although some mines may still be using older one-inch diameter 

hose. Although MSHA currently accepts this practice, there are several issues that mine 

operators must address when considering this option. 

1. The smaller diameter of the continuous miner hose may cause substantial friction 

losses for which the water system may not be able to compensate for, thus 

preventing compliance. The mine operator must be acutely aware of this 

potential problem. For continuous miners using one-inch diameter hose, 

compliance is extremely unlikely. 

2. The booster pump often provided on the section for supplying the miner hose 

may not be capable of providing either the pressure or the flow required for 

firefighting. The pump must be capable of providing at least 50 gpm at the 

required hose outlet pressure. 

3. A means must be available to quickly disconnect the miner hose from the 

continuous miner and permit the attachment of a firefighting nozzle. 

4. The miner hose can get tangled up with the miner trailing cable or hydraulic 

hoses during normal operations, thus preventing or impeding the ability to 

quickly advance this hose to other parts of the working section should a fire 

occur away from the continuous miner. 

COMPLIANCE ASSISTANCE EXAMPLES 

Example 1

The XYZ Coal Company’s No. 1 mine stores 1-3/4 inch firehose along the belt flights. A 

water flow test at the farthest hose outlet not located on the section indicates that at 50 

gpm, 75 psig is available. Does this comply with the standard? 

From the table in Appendix A, the friction loss in 500 feet of 1-3/4 inch firehose is 19 

psi, for a minimum required available pressure of 69 psig. Since the available pressure 

(75 psig) is greater than the required pressure (69 psig), the mine is in compliance with 

the standard for all other areas of the mine. 

Example 2

At this same mine above, the continuous miner hose is planned for use as the fire 

fighting hose on the section. The miner hose is 700 feet of 1-1/4 inch rubber hose. The 

hose is fed by a booster pump at the section mouth. The discharge from the pump is 

tested and found to produce a pressure of 175 psig at 50 gpm. Does this comply with 

the standard? 

From the table in Appendix A, the friction loss in 700 feet of 1-1/4 inch hose is 140 psi, 

for a minimum required available pressure of 190 psig. Since the available pressure 

(175 psig) is less than the required pressure (190 psig), the mine is not in compliance 

with the standard for the working section of the mine. 
11

One solution in this particular case would be to store 700 feet of 1-3/4 inch firehose on 

the section with the intent of using the firehose instead of the miner hose to fight a fire. 

In this case, the required pressure is found from the table to be 77 psig at 50 gpm, well 

within the capability of the given arrangement. 

WATER SYSTEM IMPROVEMENTS 

It should be noted with great caution that where compliance does not exist, the solution 

may not always be as simple as changing the size of the hose. An engineering 

evaluation of the water system may be necessary and may reveal a more extensive 

solution is necessary. The evaluation may also highlight the availability of more than 

one possible solution, or the potential use of a combination of solutions for the most 

economical and reliable fix. 

When the mine cannot meet the performance standard, the water system must be 

modified or enhanced sufficiently to bring the mine water supply back into compliance. 

Improvement strategies can sometimes include changing waterlines to bigger pipes, 

adding parallel waterlines, relocating gravity fed sources to higher elevations, adding 

booster pumps, or adding additional water sources. 

In planning mine water system improvements, mine operators must take into account 

the requirement for fire hose to have burst pressure ratings at least four times the 

maximum expected working pressure available at each VFO. Additionally, the 

maximum pressure available at the nozzle must not exceed 100 psig. 

Where improvements are needed to the water system, MSHA Technical Support can be 

contacted for additional assistance. 

NATIONALLY RECOGNIZED CONSESUS STANDARDS 

Nothing in any of the regulatory standards prohibits the mine operator from having 

waterlines capable of delivering a greater flow or having more outlets than required. In 

fact, experience has shown that it is often necessary to provide adequate flow and 

pressure to three or more hose lines simultaneously in order to effectively fight an 

underground coal mine fire. This expectation of flowing at least three hose lines for a 

total of at least 150 gpm at nozzle pressures of at least 50 psig, is reflected in the national 

consensus standard on underground coal mine fire protection published by the 

National Fire Protection Association. [NFPA 120-2004: Standard for Fire Prevention and 

Control in Coal Mines.] 

MSHA highly recommends that when mine operators are evaluating the needs of planned 

new mines, or re-evaluating the needs of existing mines, they should give serious 

consideration to meeting the recommendations of the NFPA 120 standard. 
12

PROGRAM POLICY LETTER NO. P11-V-15 – APPENDIX C 

SUBJECT: Water Delivery Capability of Underground Coal Mine Waterlines Used 

for Firefighting Purposes When Fighting a Fire with a Firehose and 

Attached Nozzle 

Waterline Compliance Test Device and Bill of Material

A

Ba 

Bb 

C

D1

E 

D2

F

G

H
13

BILL OF MATERIAL

Item ID Description Notes

A Liquid filled bourdon tube pressure gage 1 

Ba 1⁄4” female NPT by 1⁄4” industrial male quick connect plug 2 

Bb 1⁄4” male NPT by 1⁄4” universal female quick connect recepticle 2 

C 3⁄4” by 1⁄4” hexnut reducer bushing 3 

D1 1-1/2” by 3⁄4” hexnut reducer bushing 3 

D2 1-1/2” by 3⁄4” hexnut reducer bushing 3 

E 1-1/2” threaded straight pipe tee 3 

F Calibrated orifice with 1⁄2” NPT male threads 5 

G 3⁄4” by 1⁄2” hexnut reducer bushing 3 

H light-weight anodized aluminum hose/pipe adapter, Redhead 

Model 54RL, 1-1/2” male NPT by 1-1/2” female NPSH swivel 

with gasket (or equivalent) 

4 

NOTE 1: Pressure gage scale should be such that the required flow pressure should be 

approximately at half scale, or greater. 

NOTE 2: The “air chuck quick connection” is optional. The pressure gage can 

alternatively be screwed directly into the hex reducer bushing (Item C). However, the 

quick connect allows the gage to be easily turned in any direction for better visibility 

during the test, and it allows for easy removal for storage. 

NOTE 3: The fittings shown are galvanized, threaded Class 125 standard gray cast iron 

fittings. These fittings have a water pressure rating of 175 psig, which should be 

adequate for most flow test scenarios. If higher flow pressures are expected, then higher 

pressure rated fittings must be used. 

NOTE 4: This adapter fitting is optional since the pipe tee (Item E) can be threaded 

directly onto a 1-1/2 inch NPT hose outlet. However, the adapter allows the test device 

to be easily turned in any direction for aiming the stream in the most appropriate 

location, and permits tightening/untightening by hand or with a small firehose spanner 

wrench rather than a pipe wrench. 

NOTE 5: Contact MSHA Technical Support for specific information on calibrated 

orifices.