MI Fire Sprinkler cheat sheet

NFPA 13 governs commercial sprinkler design; NFPA 13R covers residential occupancies up to and including four stories; NFPA 13D covers one- and two-family dwellings and manufactured homes.

Light hazard density starts at 0.10 gpm/ft² over 1,500 ft²; ordinary hazard Group 1 is 0.15 gpm/ft² over 1,500 ft²; ordinary hazard Group 2 is 0.20 gpm/ft² over 1,500 ft².

Design area may be reduced for dry systems by 30% (not below 1,500 ft²) and for sloped ceilings by 30% (not below 1,500 ft²); reductions are not cumulative.

Minimum end-of-line pressure for a single sprinkler is 7 psi; each sprinkler in a multi-sprinkler design area must flow at least 7 psi.

Branch line spacing maximum is 15 ft for light hazard and 12 ft for ordinary hazard; maximum sprinkler-to-wall distance is half the branch line spacing.

Standard spray upright and pendant spacing maximum is 15 ft; extended coverage sprinklers allow up to 20 ft by 20 ft per NFPA 13.

A 4-inch main is the minimum for most light and ordinary hazard systems; the riser must be at least the size of the largest main it feeds.

Hydraulic design uses the Hazen-Williams formula: P = 4.52 Q^1.85 / (C^1.85 d^4.87), where P is psi per foot of pipe, Q is gpm, C is the roughness coefficient, and d is inside diameter in inches.

The Michigan Fire Prevention Code, Public Act 207 of 1941, is administered by the Bureau of Fire Services within the Department of Licensing and Regulatory Affairs (LARA).

The Michigan Administrative Code rules for fire safety are codified in the Michigan Administrative Code; the sprinkler-related rules adopt NFPA 13 by reference with state amendments.

Michigan requires sprinkler protection in certain high-rise buildings, covered malls, and institutional occupancies per the adopted code; local municipalities may adopt stricter amendments.

Fire safety inspections in Michigan are performed by the Bureau of Fire Services or by a local fire department that has been delegated authority by the state.

Michigan's Fire Safety Board reviews and recommends code amendments; the Board meets on a published schedule and accepts public comment.

Violations of the Fire Prevention Code can result in civil penalties, order to vacate, or injunctive relief; the Bureau may issue a stop-work order for unpermitted installations.

Michigan adopts the International Fire Code with state amendments; the applicable edition is published by LARA and supersedes the model code where conflicts exist.

Plan review and inspection fees are set by the Bureau of Fire Services fee schedule and must be submitted with the application for a permit.

Michigan fire sprinkler contractors must be licensed by the state and must employ at least one licensed fire sprinkler contractor or responsible managing employee.

A fire sprinkler contractor license is distinct from a mechanical contractor license; the two are not interchangeable in Michigan.

Contractors must carry general liability insurance and workers' compensation insurance as a condition of licensure; proof is filed with the state.

Michigan's contractor licensing rules require continuing education and renewal on a multi-year cycle; failure to renew results in license lapse.

Contractors must provide a written contract that includes scope, price, payment schedule, and warranty terms; the contract must comply with the Michigan Consumer Protection Act.

Michigan's prompt payment act requires owners to pay contractors within a defined period after a proper invoice; retainage is limited by statute on public projects.

Lien rights: a construction lien must be recorded within 90 days of the last furnishing of labor or materials; a notice of furnishing is required for subcontractors.

Bidding errors and change orders must be documented in writing; oral change orders are enforceable only if supported by evidence of agreement and consideration.

Available water supply is determined by a flow test: static pressure, residual pressure, and flow in gpm; results are plotted on semi-log paper to establish the supply curve.

The N^1.85 graph method: plot flow at the static pressure and at the residual pressure, connect with a straight line on semi-log paper; the intersection with the system demand curve gives the required supply.

Hazen-Williams C values: 120 for unlined cast iron, 130 for galvanized steel, 140 for copper, 150 for plastic (CPVC/PEX).

Friction loss per foot = 4.52 Q^1.85 / (C^1.85 d^4.87); multiply by equivalent pipe length including fittings to get total loss.

Equivalent length of fittings: 90° elbow adds about 5 ft of pipe; tee adds about 10 ft; gate valve adds about 1 ft; check valve adds about 5 ft for 2-inch pipe.

Elevation change: 0.433 psi per foot of rise; a 10-foot rise reduces available pressure by 4.33 psi.

The system demand point is the sum of sprinkler flow at the design density plus hose allowance (typically 100-250 gpm depending on hazard) at the base of the riser.

Pump curves: a booster pump adds pressure; the operating point is where the pump curve intersects the system curve; a fire pump must be sized for the maximum demand with no less than 150% of rated flow at 65% of rated head.

NFPA 25 governs inspection, testing, and maintenance; the 2020 edition requires quarterly inspections of gauges, control valves, and alarm devices.

Main drain flow test annually: record static and residual pressure; a flow test confirms the supply valve is open and the system is unobstructed.

Sprinkler heads must be replaced if they show signs of leakage, corrosion, physical damage, or if they have been painted or coated.

Sprinkler heads have a 50-year service life for quick-response and 75-year for standard-response heads; replacement is required at end of life per NFPA 25.

Dry pipe systems require an annual trip test and a 3-year internal inspection of the dry pipe valve; the valve must be trip-tested and the system drained.

Alarm and supervisory devices must be tested annually; waterflow alarms must activate within 90 seconds of flow.

Fire pump testing is weekly (no-flow) and annual (full-flow); records must be kept and made available to the authority having jurisdiction.

Impairment procedures: when a system is out of service for more than 4 hours in a 24-hour period, the AHJ and insurance carrier must be notified and a fire watch implemented.

A permit application must be submitted to the Bureau of Fire Services or delegated local authority before installation; work cannot begin until the permit is issued.

Plan submittals must include hydraulic calculations, sprinkler layout, water supply flow test data, and manufacturer cut sheets for all devices.

Plan review is typically completed within 10-30 business days; the reviewer may issue comments requiring revisions before approval.

Approved plans must be kept on the job site and made available to the inspector at all times; deviations require a revised submittal.

A certificate of occupancy cannot be issued until the sprinkler system passes final inspection and the contractor submits as-built drawings.

Final inspection includes verification of hydraulic design, sprinkler spacing, clearance, and testing of alarms and main drain.

Michigan requires that plans be sealed by a licensed professional engineer or architect when required by the building code; residential 13D plans may be prepared by the contractor.

As-built drawings must reflect actual installed conditions and be submitted within a specified time after completion; they become part of the permanent record.

NFPA 13 governs commercial sprinkler design; NFPA 13R covers residential occupancies up to and including four stories; NFPA 13D covers one- and two-family dwellings and manufactured homes.

Light hazard density starts at 0.10 gpm/ft² over 1,500 ft²; ordinary hazard Group 1 is 0.15 gpm/ft² over 1,500 ft²; ordinary hazard Group 2 is 0.20 gpm/ft² over 1,500 ft².

Design area may be reduced for dry systems by 30% (not below 1,500 ft²) and for sloped ceilings by 30% (not below 1,500 ft²); reductions are not cumulative.

Minimum end-of-line pressure for a single sprinkler is 7 psi; each sprinkler in a multi-sprinkler design area must flow at least 7 psi.

Branch line spacing maximum is 15 ft for light hazard and 12 ft for ordinary hazard; maximum sprinkler-to-wall distance is half the branch line spacing.

Standard spray upright and pendant spacing maximum is 15 ft; extended coverage sprinklers allow up to 20 ft by 20 ft per NFPA 13.

A 4-inch main is the minimum for most light and ordinary hazard systems; the riser must be at least the size of the largest main it feeds.

Hydraulic design uses the Hazen-Williams formula: P = 4.52 Q^1.85 / (C^1.85 d^4.87), where P is psi per foot of pipe, Q is gpm, C is the roughness coefficient, and d is inside diameter in inches.

The Michigan Fire Prevention Code, Public Act 207 of 1941, is administered by the Bureau of Fire Services within the Department of Licensing and Regulatory Affairs (LARA).

The Michigan Administrative Code rules for fire safety are codified in the Michigan Administrative Code; the sprinkler-related rules adopt NFPA 13 by reference with state amendments.

Michigan requires sprinkler protection in certain high-rise buildings, covered malls, and institutional occupancies per the adopted code; local municipalities may adopt stricter amendments.

Fire safety inspections in Michigan are performed by the Bureau of Fire Services or by a local fire department that has been delegated authority by the state.

Michigan's Fire Safety Board reviews and recommends code amendments; the Board meets on a published schedule and accepts public comment.

Violations of the Fire Prevention Code can result in civil penalties, order to vacate, or injunctive relief; the Bureau may issue a stop-work order for unpermitted installations.

Michigan adopts the International Fire Code with state amendments; the applicable edition is published by LARA and supersedes the model code where conflicts exist.

Plan review and inspection fees are set by the Bureau of Fire Services fee schedule and must be submitted with the application for a permit.

Michigan fire sprinkler contractors must be licensed by the state and must employ at least one licensed fire sprinkler contractor or responsible managing employee.

A fire sprinkler contractor license is distinct from a mechanical contractor license; the two are not interchangeable in Michigan.

Contractors must carry general liability insurance and workers' compensation insurance as a condition of licensure; proof is filed with the state.

Michigan's contractor licensing rules require continuing education and renewal on a multi-year cycle; failure to renew results in license lapse.

Contractors must provide a written contract that includes scope, price, payment schedule, and warranty terms; the contract must comply with the Michigan Consumer Protection Act.

Michigan's prompt payment act requires owners to pay contractors within a defined period after a proper invoice; retainage is limited by statute on public projects.

Lien rights: a construction lien must be recorded within 90 days of the last furnishing of labor or materials; a notice of furnishing is required for subcontractors.

Bidding errors and change orders must be documented in writing; oral change orders are enforceable only if supported by evidence of agreement and consideration.

Available water supply is determined by a flow test: static pressure, residual pressure, and flow in gpm; results are plotted on semi-log paper to establish the supply curve.

The N^1.85 graph method: plot flow at the static pressure and at the residual pressure, connect with a straight line on semi-log paper; the intersection with the system demand curve gives the required supply.

Hazen-Williams C values: 120 for unlined cast iron, 130 for galvanized steel, 140 for copper, 150 for plastic (CPVC/PEX).

Friction loss per foot = 4.52 Q^1.85 / (C^1.85 d^4.87); multiply by equivalent pipe length including fittings to get total loss.

Equivalent length of fittings: 90° elbow adds about 5 ft of pipe; tee adds about 10 ft; gate valve adds about 1 ft; check valve adds about 5 ft for 2-inch pipe.

Elevation change: 0.433 psi per foot of rise; a 10-foot rise reduces available pressure by 4.33 psi.

The system demand point is the sum of sprinkler flow at the design density plus hose allowance (typically 100-250 gpm depending on hazard) at the base of the riser.

Pump curves: a booster pump adds pressure; the operating point is where the pump curve intersects the system curve; a fire pump must be sized for the maximum demand with no less than 150% of rated flow at 65% of rated head.

NFPA 25 governs inspection, testing, and maintenance; the 2020 edition requires quarterly inspections of gauges, control valves, and alarm devices.

Main drain flow test annually: record static and residual pressure; a flow test confirms the supply valve is open and the system is unobstructed.

Sprinkler heads must be replaced if they show signs of leakage, corrosion, physical damage, or if they have been painted or coated.

Sprinkler heads have a 50-year service life for quick-response and 75-year for standard-response heads; replacement is required at end of life per NFPA 25.

Dry pipe systems require an annual trip test and a 3-year internal inspection of the dry pipe valve; the valve must be trip-tested and the system drained.

Alarm and supervisory devices must be tested annually; waterflow alarms must activate within 90 seconds of flow.

Fire pump testing is weekly (no-flow) and annual (full-flow); records must be kept and made available to the authority having jurisdiction.

Impairment procedures: when a system is out of service for more than 4 hours in a 24-hour period, the AHJ and insurance carrier must be notified and a fire watch implemented.

A permit application must be submitted to the Bureau of Fire Services or delegated local authority before installation; work cannot begin until the permit is issued.

Plan submittals must include hydraulic calculations, sprinkler layout, water supply flow test data, and manufacturer cut sheets for all devices.

Plan review is typically completed within 10-30 business days; the reviewer may issue comments requiring revisions before approval.

Approved plans must be kept on the job site and made available to the inspector at all times; deviations require a revised submittal.

A certificate of occupancy cannot be issued until the sprinkler system passes final inspection and the contractor submits as-built drawings.

Final inspection includes verification of hydraulic design, sprinkler spacing, clearance, and testing of alarms and main drain.

Michigan requires that plans be sealed by a licensed professional engineer or architect when required by the building code; residential 13D plans may be prepared by the contractor.

As-built drawings must reflect actual installed conditions and be submitted within a specified time after completion; they become part of the permanent record.

NFPA 13 governs commercial sprinkler design; NFPA 13R covers residential occupancies up to and including four stories; NFPA 13D covers one- and two-family dwellings and manufactured homes.

Light hazard density starts at 0.10 gpm/ft² over 1,500 ft²; ordinary hazard Group 1 is 0.15 gpm/ft² over 1,500 ft²; ordinary hazard Group 2 is 0.20 gpm/ft² over 1,500 ft².

Design area may be reduced for dry systems by 30% (not below 1,500 ft²) and for sloped ceilings by 30% (not below 1,500 ft²); reductions are not cumulative.

Minimum end-of-line pressure for a single sprinkler is 7 psi; each sprinkler in a multi-sprinkler design area must flow at least 7 psi.

Branch line spacing maximum is 15 ft for light hazard and 12 ft for ordinary hazard; maximum sprinkler-to-wall distance is half the branch line spacing.

Standard spray upright and pendant spacing maximum is 15 ft; extended coverage sprinklers allow up to 20 ft by 20 ft per NFPA 13.

A 4-inch main is the minimum for most light and ordinary hazard systems; the riser must be at least the size of the largest main it feeds.

Hydraulic design uses the Hazen-Williams formula: P = 4.52 Q^1.85 / (C^1.85 d^4.87), where P is psi per foot of pipe, Q is gpm, C is the roughness coefficient, and d is inside diameter in inches.

The Michigan Fire Prevention Code, Public Act 207 of 1941, is administered by the Bureau of Fire Services within the Department of Licensing and Regulatory Affairs (LARA).

The Michigan Administrative Code rules for fire safety are codified in the Michigan Administrative Code; the sprinkler-related rules adopt NFPA 13 by reference with state amendments.

Michigan requires sprinkler protection in certain high-rise buildings, covered malls, and institutional occupancies per the adopted code; local municipalities may adopt stricter amendments.

Fire safety inspections in Michigan are performed by the Bureau of Fire Services or by a local fire department that has been delegated authority by the state.

Michigan's Fire Safety Board reviews and recommends code amendments; the Board meets on a published schedule and accepts public comment.

Violations of the Fire Prevention Code can result in civil penalties, order to vacate, or injunctive relief; the Bureau may issue a stop-work order for unpermitted installations.

Michigan adopts the International Fire Code with state amendments; the applicable edition is published by LARA and supersedes the model code where conflicts exist.

Plan review and inspection fees are set by the Bureau of Fire Services fee schedule and must be submitted with the application for a permit.

Michigan fire sprinkler contractors must be licensed by the state and must employ at least one licensed fire sprinkler contractor or responsible managing employee.

A fire sprinkler contractor license is distinct from a mechanical contractor license; the two are not interchangeable in Michigan.

Contractors must carry general liability insurance and workers' compensation insurance as a condition of licensure; proof is filed with the state.

Michigan's contractor licensing rules require continuing education and renewal on a multi-year cycle; failure to renew results in license lapse.

Contractors must provide a written contract that includes scope, price, payment schedule, and warranty terms; the contract must comply with the Michigan Consumer Protection Act.

Michigan's prompt payment act requires owners to pay contractors within a defined period after a proper invoice; retainage is limited by statute on public projects.

Lien rights: a construction lien must be recorded within 90 days of the last furnishing of labor or materials; a notice of furnishing is required for subcontractors.

Bidding errors and change orders must be documented in writing; oral change orders are enforceable only if supported by evidence of agreement and consideration.

Available water supply is determined by a flow test: static pressure, residual pressure, and flow in gpm; results are plotted on semi-log paper to establish the supply curve.

The N^1.85 graph method: plot flow at the static pressure and at the residual pressure, connect with a straight line on semi-log paper; the intersection with the system demand curve gives the required supply.

Hazen-Williams C values: 120 for unlined cast iron, 130 for galvanized steel, 140 for copper, 150 for plastic (CPVC/PEX).

Friction loss per foot = 4.52 Q^1.85 / (C^1.85 d^4.87); multiply by equivalent pipe length including fittings to get total loss.

Equivalent length of fittings: 90° elbow adds about 5 ft of pipe; tee adds about 10 ft; gate valve adds about 1 ft; check valve adds about 5 ft for 2-inch pipe.

Elevation change: 0.433 psi per foot of rise; a 10-foot rise reduces available pressure by 4.33 psi.

The system demand point is the sum of sprinkler flow at the design density plus hose allowance (typically 100-250 gpm depending on hazard) at the base of the riser.

Pump curves: a booster pump adds pressure; the operating point is where the pump curve intersects the system curve; a fire pump must be sized for the maximum demand with no less than 150% of rated flow at 65% of rated head.

NFPA 25 governs inspection, testing, and maintenance; the 2020 edition requires quarterly inspections of gauges, control valves, and alarm devices.

Main drain flow test annually: record static and residual pressure; a flow test confirms the supply valve is open and the system is unobstructed.

Sprinkler heads must be replaced if they show signs of leakage, corrosion, physical damage, or if they have been painted or coated.

Sprinkler heads have a 50-year service life for quick-response and 75-year for standard-response heads; replacement is required at end of life per NFPA 25.

Dry pipe systems require an annual trip test and a 3-year internal inspection of the dry pipe valve; the valve must be trip-tested and the system drained.

Alarm and supervisory devices must be tested annually; waterflow alarms must activate within 90 seconds of flow.

Fire pump testing is weekly (no-flow) and annual (full-flow); records must be kept and made available to the authority having jurisdiction.

Impairment procedures: when a system is out of service for more than 4 hours in a 24-hour period, the AHJ and insurance carrier must be notified and a fire watch implemented.

A permit application must be submitted to the Bureau of Fire Services or delegated local authority before installation; work cannot begin until the permit is issued.

Plan submittals must include hydraulic calculations, sprinkler layout, water supply flow test data, and manufacturer cut sheets for all devices.

Plan review is typically completed within 10-30 business days; the reviewer may issue comments requiring revisions before approval.

Approved plans must be kept on the job site and made available to the inspector at all times; deviations require a revised submittal.

A certificate of occupancy cannot be issued until the sprinkler system passes final inspection and the contractor submits as-built drawings.

Final inspection includes verification of hydraulic design, sprinkler spacing, clearance, and testing of alarms and main drain.

Michigan requires that plans be sealed by a licensed professional engineer or architect when required by the building code; residential 13D plans may be prepared by the contractor.

As-built drawings must reflect actual installed conditions and be submitted within a specified time after completion; they become part of the permanent record.

NFPA 13 governs commercial sprinkler design; NFPA 13R covers residential occupancies up to and including four stories; NFPA 13D covers one- and two-family dwellings and manufactured homes.

Light hazard density starts at 0.10 gpm/ft² over 1,500 ft²; ordinary hazard Group 1 is 0.15 gpm/ft² over 1,500 ft²; ordinary hazard Group 2 is 0.20 gpm/ft² over 1,500 ft².

Design area may be reduced for dry systems by 30% (not below 1,500 ft²) and for sloped ceilings by 30% (not below 1,500 ft²); reductions are not cumulative.

Minimum end-of-line pressure for a single sprinkler is 7 psi; each sprinkler in a multi-sprinkler design area must flow at least 7 psi.

Branch line spacing maximum is 15 ft for light hazard and 12 ft for ordinary hazard; maximum sprinkler-to-wall distance is half the branch line spacing.

Standard spray upright and pendant spacing maximum is 15 ft; extended coverage sprinklers allow up to 20 ft by 20 ft per NFPA 13.

A 4-inch main is the minimum for most light and ordinary hazard systems; the riser must be at least the size of the largest main it feeds.

Hydraulic design uses the Hazen-Williams formula: P = 4.52 Q^1.85 / (C^1.85 d^4.87), where P is psi per foot of pipe, Q is gpm, C is the roughness coefficient, and d is inside diameter in inches.

The Michigan Fire Prevention Code, Public Act 207 of 1941, is administered by the Bureau of Fire Services within the Department of Licensing and Regulatory Affairs (LARA).

The Michigan Administrative Code rules for fire safety are codified in the Michigan Administrative Code; the sprinkler-related rules adopt NFPA 13 by reference with state amendments.

Michigan requires sprinkler protection in certain high-rise buildings, covered malls, and institutional occupancies per the adopted code; local municipalities may adopt stricter amendments.

Fire safety inspections in Michigan are performed by the Bureau of Fire Services or by a local fire department that has been delegated authority by the state.

Michigan's Fire Safety Board reviews and recommends code amendments; the Board meets on a published schedule and accepts public comment.

Violations of the Fire Prevention Code can result in civil penalties, order to vacate, or injunctive relief; the Bureau may issue a stop-work order for unpermitted installations.

Michigan adopts the International Fire Code with state amendments; the applicable edition is published by LARA and supersedes the model code where conflicts exist.

Plan review and inspection fees are set by the Bureau of Fire Services fee schedule and must be submitted with the application for a permit.

Michigan fire sprinkler contractors must be licensed by the state and must employ at least one licensed fire sprinkler contractor or responsible managing employee.

A fire sprinkler contractor license is distinct from a mechanical contractor license; the two are not interchangeable in Michigan.

Contractors must carry general liability insurance and workers' compensation insurance as a condition of licensure; proof is filed with the state.

Michigan's contractor licensing rules require continuing education and renewal on a multi-year cycle; failure to renew results in license lapse.

Contractors must provide a written contract that includes scope, price, payment schedule, and warranty terms; the contract must comply with the Michigan Consumer Protection Act.

Michigan's prompt payment act requires owners to pay contractors within a defined period after a proper invoice; retainage is limited by statute on public projects.

Lien rights: a construction lien must be recorded within 90 days of the last furnishing of labor or materials; a notice of furnishing is required for subcontractors.

Bidding errors and change orders must be documented in writing; oral change orders are enforceable only if supported by evidence of agreement and consideration.

Available water supply is determined by a flow test: static pressure, residual pressure, and flow in gpm; results are plotted on semi-log paper to establish the supply curve.

The N^1.85 graph method: plot flow at the static pressure and at the residual pressure, connect with a straight line on semi-log paper; the intersection with the system demand curve gives the required supply.

Hazen-Williams C values: 120 for unlined cast iron, 130 for galvanized steel, 140 for copper, 150 for plastic (CPVC/PEX).

Friction loss per foot = 4.52 Q^1.85 / (C^1.85 d^4.87); multiply by equivalent pipe length including fittings to get total loss.

Equivalent length of fittings: 90° elbow adds about 5 ft of pipe; tee adds about 10 ft; gate valve adds about 1 ft; check valve adds about 5 ft for 2-inch pipe.

Elevation change: 0.433 psi per foot of rise; a 10-foot rise reduces available pressure by 4.33 psi.

The system demand point is the sum of sprinkler flow at the design density plus hose allowance (typically 100-250 gpm depending on hazard) at the base of the riser.

Pump curves: a booster pump adds pressure; the operating point is where the pump curve intersects the system curve; a fire pump must be sized for the maximum demand with no less than 150% of rated flow at 65% of rated head.

NFPA 25 governs inspection, testing, and maintenance; the 2020 edition requires quarterly inspections of gauges, control valves, and alarm devices.

Main drain flow test annually: record static and residual pressure; a flow test confirms the supply valve is open and the system is unobstructed.

Sprinkler heads must be replaced if they show signs of leakage, corrosion, physical damage, or if they have been painted or coated.

Sprinkler heads have a 50-year service life for quick-response and 75-year for standard-response heads; replacement is required at end of life per NFPA 25.

Dry pipe systems require an annual trip test and a 3-year internal inspection of the dry pipe valve; the valve must be trip-tested and the system drained.

Alarm and supervisory devices must be tested annually; waterflow alarms must activate within 90 seconds of flow.

Fire pump testing is weekly (no-flow) and annual (full-flow); records must be kept and made available to the authority having jurisdiction.

Impairment procedures: when a system is out of service for more than 4 hours in a 24-hour period, the AHJ and insurance carrier must be notified and a fire watch implemented.

A permit application must be submitted to the Bureau of Fire Services or delegated local authority before installation; work cannot begin until the permit is issued.

Plan submittals must include hydraulic calculations, sprinkler layout, water supply flow test data, and manufacturer cut sheets for all devices.

Plan review is typically completed within 10-30 business days; the reviewer may issue comments requiring revisions before approval.

Approved plans must be kept on the job site and made available to the inspector at all times; deviations require a revised submittal.

A certificate of occupancy cannot be issued until the sprinkler system passes final inspection and the contractor submits as-built drawings.

Final inspection includes verification of hydraulic design, sprinkler spacing, clearance, and testing of alarms and main drain.

Michigan requires that plans be sealed by a licensed professional engineer or architect when required by the building code; residential 13D plans may be prepared by the contractor.

As-built drawings must reflect actual installed conditions and be submitted within a specified time after completion; they become part of the permanent record.

NFPA 13 governs commercial sprinkler design; NFPA 13R covers residential occupancies up to and including four stories; NFPA 13D covers one- and two-family dwellings and manufactured homes.

Light hazard density starts at 0.10 gpm/ft² over 1,500 ft²; ordinary hazard Group 1 is 0.15 gpm/ft² over 1,500 ft²; ordinary hazard Group 2 is 0.20 gpm/ft² over 1,500 ft².

Design area may be reduced for dry systems by 30% (not below 1,500 ft²) and for sloped ceilings by 30% (not below 1,500 ft²); reductions are not cumulative.

Minimum end-of-line pressure for a single sprinkler is 7 psi; each sprinkler in a multi-sprinkler design area must flow at least 7 psi.

Branch line spacing maximum is 15 ft for light hazard and 12 ft for ordinary hazard; maximum sprinkler-to-wall distance is half the branch line spacing.

Standard spray upright and pendant spacing maximum is 15 ft; extended coverage sprinklers allow up to 20 ft by 20 ft per NFPA 13.

A 4-inch main is the minimum for most light and ordinary hazard systems; the riser must be at least the size of the largest main it feeds.

Hydraulic design uses the Hazen-Williams formula: P = 4.52 Q^1.85 / (C^1.85 d^4.87), where P is psi per foot of pipe, Q is gpm, C is the roughness coefficient, and d is inside diameter in inches.

The Michigan Fire Prevention Code, Public Act 207 of 1941, is administered by the Bureau of Fire Services within the Department of Licensing and Regulatory Affairs (LARA).

The Michigan Administrative Code rules for fire safety are codified in the Michigan Administrative Code; the sprinkler-related rules adopt NFPA 13 by reference with state amendments.

Michigan requires sprinkler protection in certain high-rise buildings, covered malls, and institutional occupancies per the adopted code; local municipalities may adopt stricter amendments.

Fire safety inspections in Michigan are performed by the Bureau of Fire Services or by a local fire department that has been delegated authority by the state.

Michigan's Fire Safety Board reviews and recommends code amendments; the Board meets on a published schedule and accepts public comment.

Violations of the Fire Prevention Code can result in civil penalties, order to vacate, or injunctive relief; the Bureau may issue a stop-work order for unpermitted installations.

Michigan adopts the International Fire Code with state amendments; the applicable edition is published by LARA and supersedes the model code where conflicts exist.

Plan review and inspection fees are set by the Bureau of Fire Services fee schedule and must be submitted with the application for a permit.

Michigan fire sprinkler contractors must be licensed by the state and must employ at least one licensed fire sprinkler contractor or responsible managing employee.

A fire sprinkler contractor license is distinct from a mechanical contractor license; the two are not interchangeable in Michigan.

Contractors must carry general liability insurance and workers' compensation insurance as a condition of licensure; proof is filed with the state.

Michigan's contractor licensing rules require continuing education and renewal on a multi-year cycle; failure to renew results in license lapse.

Contractors must provide a written contract that includes scope, price, payment schedule, and warranty terms; the contract must comply with the Michigan Consumer Protection Act.

Michigan's prompt payment act requires owners to pay contractors within a defined period after a proper invoice; retainage is limited by statute on public projects.

Lien rights: a construction lien must be recorded within 90 days of the last furnishing of labor or materials; a notice of furnishing is required for subcontractors.

Bidding errors and change orders must be documented in writing; oral change orders are enforceable only if supported by evidence of agreement and consideration.

Available water supply is determined by a flow test: static pressure, residual pressure, and flow in gpm; results are plotted on semi-log paper to establish the supply curve.

The N^1.85 graph method: plot flow at the static pressure and at the residual pressure, connect with a straight line on semi-log paper; the intersection with the system demand curve gives the required supply.

Hazen-Williams C values: 120 for unlined cast iron, 130 for galvanized steel, 140 for copper, 150 for plastic (CPVC/PEX).

Friction loss per foot = 4.52 Q^1.85 / (C^1.85 d^4.87); multiply by equivalent pipe length including fittings to get total loss.

Equivalent length of fittings: 90° elbow adds about 5 ft of pipe; tee adds about 10 ft; gate valve adds about 1 ft; check valve adds about 5 ft for 2-inch pipe.

Elevation change: 0.433 psi per foot of rise; a 10-foot rise reduces available pressure by 4.33 psi.

The system demand point is the sum of sprinkler flow at the design density plus hose allowance (typically 100-250 gpm depending on hazard) at the base of the riser.

Pump curves: a booster pump adds pressure; the operating point is where the pump curve intersects the system curve; a fire pump must be sized for the maximum demand with no less than 150% of rated flow at 65% of rated head.

NFPA 25 governs inspection, testing, and maintenance; the 2020 edition requires quarterly inspections of gauges, control valves, and alarm devices.

Main drain flow test annually: record static and residual pressure; a flow test confirms the supply valve is open and the system is unobstructed.

Sprinkler heads must be replaced if they show signs of leakage, corrosion, physical damage, or if they have been painted or coated.

Sprinkler heads have a 50-year service life for quick-response and 75-year for standard-response heads; replacement is required at end of life per NFPA 25.

Dry pipe systems require an annual trip test and a 3-year internal inspection of the dry pipe valve; the valve must be trip-tested and the system drained.

Alarm and supervisory devices must be tested annually; waterflow alarms must activate within 90 seconds of flow.

Fire pump testing is weekly (no-flow) and annual (full-flow); records must be kept and made available to the authority having jurisdiction.

Impairment procedures: when a system is out of service for more than 4 hours in a 24-hour period, the AHJ and insurance carrier must be notified and a fire watch implemented.

A permit application must be submitted to the Bureau of Fire Services or delegated local authority before installation; work cannot begin until the permit is issued.

Plan submittals must include hydraulic calculations, sprinkler layout, water supply flow test data, and manufacturer cut sheets for all devices.

Plan review is typically completed within 10-30 business days; the reviewer may issue comments requiring revisions before approval.

Approved plans must be kept on the job site and made available to the inspector at all times; deviations require a revised submittal.

A certificate of occupancy cannot be issued until the sprinkler system passes final inspection and the contractor submits as-built drawings.

Final inspection includes verification of hydraulic design, sprinkler spacing, clearance, and testing of alarms and main drain.

Michigan requires that plans be sealed by a licensed professional engineer or architect when required by the building code; residential 13D plans may be prepared by the contractor.

As-built drawings must reflect actual installed conditions and be submitted within a specified time after completion; they become part of the permanent record.