Archive for January, 2009

Minimum Hotel Bathroom Plumbing Clearance

Wednesday, January 21st, 2009

Summary:  Just how little space is required to accommodate bathroom plumbing? 

Hotel developers and architects are always complaining that engineers ask for too much space above a bathroom ceiling for plumbing.  Well, maybe they have a case.  Typically, 10 inches clear for toilet and bathtub fittings in the easy answer.  We have found a jobsite where the plumber has proven it can be done in 6 inches clear.  The picture below is from the San Diego Gas Lamp Residence Inn being plumbed by Sherwood Mechanical Contractors.  As you can see, the clear space is only the length of the pen, which measures 6 inches.  Obviously, there were no long runs with slope.  Also, this was partly made possible by full 3D shop drawings which provided excellent coordination between trades.  There is no space for random pipe crossings.  Notice that one of the sheet rock supports was trimmed to fit the trap.

Hotel Design Due Diligence – Mechanical, Electrical, Plumbing

Sunday, January 4th, 2009

Summary: The first step to designing a hotel, or any project for that matter, is a thorough due diligence.  The due diligence checklist below is a proven tool I recommend for hotel design.  The same document is available in Word format by downloading a file using this link:

 Click here to download Word document! 

If you have improvements to this checklist, please comment. 
 

ARCHITECT

 

Company:

Address:

 

Tel:

Fax:

Contacts:

 

 

 

PROJECT LOCATION

 

Address:

 

 

 

Directions:

 

 

 

APPLICABLE CODES

 

BUILDING:

MECHANICAL:

PLUMBING:

ELECTRICAL:

FIRE:

ENERGY:

Notes/Comments:

 

 

 

 

BUILDING PLAN REVIEW

 

Name:

Address:

 

Contacts:

 

Tel:

Fax:

Email:

 

Building Importance Factor:

Seismic Zone:

Equipment Screening Expectations:


MECHANICAL PLAN REVIEW

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Are there any special local amendments to the codes?

Who submits plans for review?

How is U-value for tapered roof insulation computed?

Design conditions: ____/____dry bulb/wet bulb cooling,

_____ design heating temp

            ________ extreme heating temp

 

 

 

 

PLUMBING PLAN REVIEW

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Are there any special local amendments to the codes?

Who submits plans for review?

What are plan review expectations?:

Plastic pipe allowed below slab?

CPVC allowed for distribution?

Cold water pipe insulation recommended?

Are isometric riser diagrams required?

Show fixture counts on risers only OK?

Water service back flow preventer location:

Sovent plumbing system allowed?

Other plan review data required?

 

 

 


ELECTRICAL PLAN REVIEW

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

Are there any local amendments to the codes?

Who submits plans for review?

Verify plan review expectations

NMC allowed for 3 story building?

MC allowed?

Aluminum OK for 100 amps and larger feeders?

Red fire alarm cable allowed?

Interpretation of dwelling unit vs hotel unit?

Receptacle layout greater than 12’ spacing OK per NEC 210.60(B)?

Air quality permit required for diesel emergency generators?

Documentation for fuse and breaker coordination for elevators?

 

 

 

 

 

 

FIRE MARSHAL REPRESENTATIVE

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Who submits plans to Fire Department?

Sprinkler pump required?

Fire pump required?

Emergency power for fire pump?

Hazard Classification:

Flow required per sf:

Head spacing requirements:

Attic coverage:

Coverage above A/C unit in closet?

Residual pressure required at furthest head:

Changes to pressure expected in the future due to area growth?

Air quality permit required for engine driven fire pumps?

Egress sign color (red)(green)

Egress signs high and low required? Exactly where?

Emergency power elevator?

Emergency power for other systems?

Effects of building height:

Hoods: Which fans run during fire? Hood? MUA?

Hood/MUA fans need emergency power? (only for smoke removal?)

Detectors required in which spaces?

Fire fighters’ communications system?

 

 

 

 

 

NATURAL GAS COMPANY

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Initial Application to Start Utility Engineering:

Gas available?

Size of service pipe:

Standard pressures available for service:

Rules/Publications for service:

 

 

 

 

ELECTRICAL UTILITY

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Initial Application to Start Utility Engineering:

Overhead or Underground Service?

Standard service voltages available?

Transformer: (Pad mounted) (UG)(Pole mounted):

Clearances around transformer:

Pad or vault required?

Rules/Publications for service:

Application forms for temporary service:

Contact:

Document requirements:

 

Application forms for permanent service:

Contact:

Document requirements:

 

 

 

 

CABLE TELEVISION UTILITY

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Who will be contracting for the service? Owner/Contractor/Engineer?

Rules/Publications for service:

Expectations for interface on this project:

Demarc Location:

Raceway requirements:

Longest run allowed:

Backboard:

Electrical power:

Air Conditioning requirements:

 

 

 

 

TELEPHONE / INTERNET UTILITY

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Who will be contracting for the service? Owner/Contractor/Engineer?

Rules/Publications for service:

Expectations for interface on this project:

Demarc Location:

Raceway requirements:

Longest run allowed:

Backboard:

Electrical power:

Air Conditioning requirements:

 

 

 

 

HEALTH DEPARTMENT

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Who submits plans to Health Department?

Kitchen Rule/Publications:

Pool Chemical Treatment:

Spa Chemical Treatment:

Garbage Disposers allowed?

Sizing criteria for grease interceptors:

 

 

 

 

ADA PLAN REVIEW

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Accessible room doorbell: Is light and horn required for bathroom?

 

 

 

 

CIVIL ENGINEER

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

WATER AND SEWER PROVIDER:

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

SEWER

Location of connection:

Pipe size:

Invert at point of connection:

Invert of nearest upstream manholes flood rim (back water valves):

 

WATER SERVICE PRESSURE

Static Pressure:

Residual pressure:

Basis of pressure:

Future pressure expectations:

 

FIRE SPRINKLER WATER

Location of connection:

Pipe size:

Invert at point of connection:

Flow demand:

Back flow device:

Booster Pump?

 

DOMESTIC WATER

Location of connection:

Pipe size:

Water Hardness (provide water softener if > 7 grains/gal):

Invert at point of connection:

Flow demand:

Meter location:

Back flow device:

Booster Pump Required?

 

IRRIGATION WATER

Location of connection:

Pipe size:

Flow demand:

Meter location:

Back flow device:

 

 

 

 

SOILS ENGINEER (GEOTECH)

 

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Settlement Expected:

Soil pH (corrosive)

Plastic pipe allowed below grade?

Cathodic protection required?

 

 

 

 

STRUCTURAL ENGINEER

Name:

Address:

 

Contact:

 

Tel:

Fax:

Email:

 

 

Seismic Zone:

Zone Factor:

Foundation footing locations:

Shear wall locations:

Limitations on penetrations:

 

Hot Water Recirc Booster Heaters Simplify Hotel Commissioning

Saturday, January 3rd, 2009

Summary: A small water heater in the recirc line is a simple way to avoid low flow recirc temperature drift when the storage water temperature is greater than 120 degrees.

Hot water mixing valves function effectively when hot water is in heavy use and cold water is mixing with the hot water.  However, when there is no net usage of hot water, such as at night in a hotel, the recirculation line can become progressively warm until it reaches the temperature of the hot water storage tank.  This temperature is often at 160 degrees, and the first user of hot water in the morning gets a slug of extremely hot water.  Of course, the common answer is to configure the mixing valves properly and balance the low flow condition.  The flaw in this concept is that many plumbers are not experienced in performing this work and it falls on the shoulders of the engineer to come to the hotel during the first few weeks of operation and perform the balance.

But there is a fool-proof alternative that requires no guesswork.  The method is to place a small hot water heater in the recirc line to compensate for the temperature loss in circulation.  Since the heater has its own internal thermostat, the only commissioning effort required is to set the water heater thermostat to 120 degrees.

But what BTUH rating is needed for the hot water heater?  The answer is not easy because it depends on the heat loss rate of the hot water piping in the path that is being recirculated. One could compute the heat loss of the piping, but that is an arduous task.  The approach I use is to start with the basic assumption that the recirc flow rate will be designed to achieve a return temperature with maximum temperature drop of 15 degrees.  This matches real experience where we supply 120 to 125 degree water with a return temperature of about 110 degrees.   Since we all have experience in selecting the flow rate in the risers to achieve a delta T of about 10 to 15 degrees,  this approach has a practical starting point as compared to computing the heat loss of a piping system.  So multiply the total circulation flow rate by 15 degrees and by 500.  For example, if the hotel has 20 risers with 1/2 gpm per riser, the total flow is 10 gpm.  This results in 15 degrees x 10 gpm x 500 = 75,000 BTUH.  That is a small water heater if it is gas, or a 20kw heater if it is electric.

Aside: It is interesting to think about the implications of this heat loss as it relates to energy waste.  This heat loss is not only a direct loss of heating energy, but it also requires constant mechanical cooling to remove this wasted heat.   So this is a double argument for better hot water system insulation.

Hotel Dual Electrical Services for LEED Credits

Friday, January 2nd, 2009

Summary: Requesting two service transformers with two voltages from the utility service is energy efficient and cost effective.

Large hotels generally have a 480/277 volt service provided by the utility and step-down transformers for 208/120 volt loads.  Since a hotel is largely 120 volt loads, the size of the step down transformers is about half of the capacity of the service.  This results in dual transformation of a large amount of power.  The energy efficient approach is to request two service transformers from the utility:  One transformer at 480/277 volts, the other at 208/120 volts.  The lower voltage transformer will eliminate all the losses from stepdown transformers in the hotel while keeping the utility losses the same.  For a large hotel, this is generally allowed by the utility.  The following is an example of the analysis applicable for computing energy savings from dual service transformers.

Based on an actual hotel of 333 rooms, the following LEED energy analysis was performed:

Assumptions:

Hotel Room Count:  330 guestrooms

120/208 volt load per NEC:  948 kva (Say 1000 kva)

Heat losses from distributed dry-type transformers  throughout the building:  2.0% of NEC load

Cost of electricity:  $0.08 per kwh

Load Factor:  Verified load factor data for hotels was not available at the time of this study.  However, load factor data for other facility types was available, and the data indicates a load factor of 30% to 50% is probable.  Since the load factor is an important part of this analysis, a continuing effort is in progress to obtain better load factor data specific to hotels.  However, we know that the magnetizing losses are a constant regardless of load and represent about 1% of the transformer losses based on nameplate data.  Therefore the I squared R losses will vary with load factor, but not in some fraction of a proportion.  For this study, the load factor is assumed to be included with the transformer loss number of 2%.  Peak losses for small transformers are commonly stated at 3%, which is the sizing criteria for cooling equipment.

Cooling Efficiency: Transformers located within the hotel require mechanical cooling to remove the heat generated by the transformers.  Since utility transformers are allowed to be cooled with ventilation air, there is an additional energy cost for dual transformation that must include the cost of mechanical cooling of the transformers.  This study is based on 1 kw per ton of cooling.

Computation of Savings:

Transformer energy savings per year in dollars =  1000kva x 0.02 efficiency x 8760 hrs/yr x $0.08 /kwh  =   $14,000 savings

Associated Cooling Savings =  1000kva x 0.02 efficiency x 3413BTUH/kw / 12000 BTUH per ton x 1 kw/ton x 8760 hrs/yr = $4,000 savings

Total Savings = transformer savings + cooling savings = $14,000 + $4,000 = $18,000 per year.